Replace the package name providers with module info providers

Create a new interface for the module generator to allow more customization in the providers.

Test: atest csuite-harness-tests
Test: make csuite; csuite-tradefed run csuite-app-launch --enable-module-dynamic-download --dynamic-download-args <args> --package <package>
Change-Id: I2950129b7092bd0d07b9b1eb67d2bb37e609ead3

18 files changed, 1219 insertions, 859 deletions

diff --git a/harness/src/main/java/com/android/csuite/config/ModuleGenerator.java b/harness/src/main/java/com/android/csuite/config/ModuleGenerator.java
deleted file mode 100644
index 0760085..0000000
--- a/harness/src/main/java/com/android/csuite/config/ModuleGenerator.java
+++ /dev/null
@@ -1,257 +0,0 @@
-/*
- * Copyright (C) 2020 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.csuite.config;
-
-import com.android.compatibility.common.tradefed.build.CompatibilityBuildHelper;
-import com.android.csuite.core.PackageNameProvider;
-import com.android.tradefed.build.IBuildInfo;
-import com.android.tradefed.config.IConfiguration;
-import com.android.tradefed.config.IConfigurationReceiver;
-import com.android.tradefed.config.Option;
-import com.android.tradefed.config.Option.Importance;
-import com.android.tradefed.device.DeviceNotAvailableException;
-import com.android.tradefed.invoker.TestInformation;
-import com.android.tradefed.log.LogUtil.CLog;
-import com.android.tradefed.result.ITestInvocationListener;
-import com.android.tradefed.targetprep.ITargetPreparer;
-import com.android.tradefed.testtype.IBuildReceiver;
-import com.android.tradefed.testtype.IRemoteTest;
-import com.android.tradefed.testtype.IShardableTest;
-
-import com.google.common.annotations.VisibleForTesting;
-import com.google.common.io.Resources;
-
-import java.io.IOException;
-import java.io.UncheckedIOException;
-import java.nio.charset.StandardCharsets;
-import java.nio.file.FileSystem;
-import java.nio.file.FileSystems;
-import java.nio.file.Files;
-import java.nio.file.Path;
-import java.util.Collection;
-import java.util.HashSet;
-import java.util.Set;
-
-/**
- * A tool for generating TradeFed suite modules during runtime.
- *
- * <p>This class generates module config files into TradeFed's test directory at runtime using a
- * template. Since the content of the test directory relies on what is being generated in a test
- * run, there can only be one instance executing at a given time.
- *
- * <p>The intention of this class is to generate test modules at the beginning of a test run and
- * cleans up after all tests finish, which resembles a target preparer. However, a target preparer
- * is executed after the sharding process has finished. The only way to make the generated modules
- * available for sharding without making changes to TradeFed's core code is to disguise this module
- * generator as an instance of IShardableTest and declare it separately in test plan config. This is
- * hacky, and in the long term a TradeFed centered solution is desired. For more details, see
- * go/sharding-hack-for-module-gen. Note that since the generate step is executed as a test instance
- * and cleanup step is executed as a target preparer, there should be no saved states between
- * generating and cleaning up module files.
- *
- * <p>This module generator collects package names from all PackageNameProvider objects specified in
- * the test configs.
- *
- * <h2>Syntax and usage</h2>
- *
- * <p>References to package name providers in TradeFed test configs must have the following syntax:
- *
- * <blockquote>
- *
- * <b>&lt;object type="PACKAGE_NAME_PROVIDER" class="</b><i>provider_class_name</i><b>"/&gt;</b>
- *
- * </blockquote>
- *
- * where <i>provider_class_name</i> is the fully-qualified class name of an PackageNameProvider
- * implementation class.
- */
-public final class ModuleGenerator
-        implements IRemoteTest,
-                IShardableTest,
-                IBuildReceiver,
-                ITargetPreparer,
-                IConfigurationReceiver {
-
-    @VisibleForTesting static final String MODULE_FILE_EXTENSION = ".config";
-    @VisibleForTesting static final String OPTION_TEMPLATE = "template";
-    @VisibleForTesting static final String PACKAGE_NAME_PROVIDER = "PACKAGE_NAME_PROVIDER";
-    private static final String TEMPLATE_PACKAGE_PATTERN = "\\{package\\}";
-    private static final Collection<IRemoteTest> NOT_SPLITABLE = null;
-
-    @Option(
-            name = OPTION_TEMPLATE,
-            description = "Module config template resource path.",
-            importance = Importance.ALWAYS)
-    private String mTemplate;
-
-    private final TestDirectoryProvider mTestDirectoryProvider;
-    private final ResourceLoader mResourceLoader;
-    private final FileSystem mFileSystem;
-    private IBuildInfo mBuildInfo;
-    private IConfiguration mConfiguration;
-
-    @Override
-    public void setConfiguration(IConfiguration configuration) {
-        mConfiguration = configuration;
-    }
-
-    public ModuleGenerator() {
-        this(FileSystems.getDefault());
-    }
-
-    private ModuleGenerator(FileSystem fileSystem) {
-        this(
-                fileSystem,
-                new CompatibilityTestDirectoryProvider(fileSystem),
-                new ClassResourceLoader());
-    }
-
-    @VisibleForTesting
-    ModuleGenerator(
-            FileSystem fileSystem,
-            TestDirectoryProvider testDirectoryProvider,
-            ResourceLoader resourceLoader) {
-        mFileSystem = fileSystem;
-        mTestDirectoryProvider = testDirectoryProvider;
-        mResourceLoader = resourceLoader;
-    }
-
-    @Override
-    public void run(final TestInformation testInfo, final ITestInvocationListener listener) {
-        // Intentionally left blank since this class is not really a test.
-    }
-
-    @Override
-    public void setUp(TestInformation testInfo) {
-        // Intentionally left blank.
-    }
-
-    @Override
-    public void setBuild(IBuildInfo buildInfo) {
-        mBuildInfo = buildInfo;
-    }
-
-    /**
-     * Generates test modules. Note that the implementation of this method is not related to
-     * sharding in any way.
-     */
-    @Override
-    public Collection<IRemoteTest> split() {
-        try {
-            // Executes the generate step.
-            generateModules();
-        } catch (IOException e) {
-            throw new UncheckedIOException("Failed to generate modules", e);
-        }
-
-        return NOT_SPLITABLE;
-    }
-
-    /** Cleans up generated test modules. */
-    @Override
-    public void tearDown(TestInformation testInfo, Throwable e) throws DeviceNotAvailableException {
-        // Gets build info from test info as when the class is executed as a ITargetPreparer
-        // preparer, it is not considered as a IBuildReceiver instance.
-        mBuildInfo = testInfo.getBuildInfo();
-
-        try {
-            // Executes the clean up step.
-            cleanUpModules();
-        } catch (IOException ioException) {
-            throw new UncheckedIOException("Failed to clean up generated modules", ioException);
-        }
-    }
-
-    private Set<String> getPackageNames() throws IOException {
-        Set<String> packages = new HashSet<>();
-        for (Object provider : mConfiguration.getConfigurationObjectList(PACKAGE_NAME_PROVIDER)) {
-            packages.addAll(((PackageNameProvider) provider).get());
-        }
-        return packages;
-    }
-
-    private void generateModules() throws IOException {
-        String templateContent = mResourceLoader.load(mTemplate);
-
-        for (String packageName : getPackageNames()) {
-            validatePackageName(packageName);
-            Files.write(
-                    getModulePath(packageName),
-                    templateContent.replaceAll(TEMPLATE_PACKAGE_PATTERN, packageName).getBytes());
-        }
-    }
-
-    private void cleanUpModules() throws IOException {
-        getPackageNames()
-                .forEach(
-                        packageName -> {
-                            try {
-                                Files.delete(getModulePath(packageName));
-                            } catch (IOException ioException) {
-                                CLog.e(
-                                        "Failed to delete the generated module for package "
-                                                + packageName,
-                                        ioException);
-                            }
-                        });
-    }
-
-    private Path getModulePath(String packageName) throws IOException {
-        Path testsDir = mTestDirectoryProvider.get(mBuildInfo);
-        return testsDir.resolve(packageName + MODULE_FILE_EXTENSION);
-    }
-
-    private static void validatePackageName(String packageName) {
-        if (packageName.isEmpty() || packageName.matches(".*" + TEMPLATE_PACKAGE_PATTERN + ".*")) {
-            throw new IllegalArgumentException(
-                    "Package name cannot be empty or contains package placeholder: "
-                            + TEMPLATE_PACKAGE_PATTERN);
-        }
-    }
-
-    @VisibleForTesting
-    interface ResourceLoader {
-        String load(String resourceName) throws IOException;
-    }
-
-    private static final class ClassResourceLoader implements ResourceLoader {
-        @Override
-        public String load(String resourceName) throws IOException {
-            return Resources.toString(
-                    getClass().getClassLoader().getResource(resourceName), StandardCharsets.UTF_8);
-        }
-    }
-
-    @VisibleForTesting
-    interface TestDirectoryProvider {
-        Path get(IBuildInfo buildInfo) throws IOException;
-    }
-
-    private static final class CompatibilityTestDirectoryProvider implements TestDirectoryProvider {
-        private final FileSystem mFileSystem;
-
-        private CompatibilityTestDirectoryProvider(FileSystem fileSystem) {
-            mFileSystem = fileSystem;
-        }
-
-        @Override
-        public Path get(IBuildInfo buildInfo) throws IOException {
-            return mFileSystem.getPath(
-                    new CompatibilityBuildHelper(buildInfo).getTestsDir().getPath());
-        }
-    }
-}
diff --git a/harness/src/main/java/com/android/csuite/core/CommandLinePackageNameProvider.java b/harness/src/main/java/com/android/csuite/core/CommandLinePackageNameProvider.java
deleted file mode 100644
index 33426ed..0000000
--- a/harness/src/main/java/com/android/csuite/core/CommandLinePackageNameProvider.java
+++ /dev/null
@@ -1,39 +0,0 @@
-/*
- * Copyright (C) 2021 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.csuite.core;
-
-import com.android.tradefed.config.Option;
-import com.android.tradefed.config.OptionClass;
-
-import com.google.common.annotations.VisibleForTesting;
-
-import java.util.HashSet;
-import java.util.Set;
-
-/** A package name provider that accepts package names via a command line option. */
-@OptionClass(alias = "command-line-package-name-provider")
-public final class CommandLinePackageNameProvider implements PackageNameProvider {
-    @VisibleForTesting static final String PACKAGE = "package";
-
-    @Option(name = PACKAGE, description = "App package names.")
-    private final Set<String> mPackages = new HashSet<>();
-
-    @Override
-    public Set<String> get() {
-        return mPackages;
-    }
-}
diff --git a/harness/src/main/java/com/android/csuite/core/FileBasedPackageNameProvider.java b/harness/src/main/java/com/android/csuite/core/FileBasedPackageNameProvider.java
deleted file mode 100644
index 6f6af06..0000000
--- a/harness/src/main/java/com/android/csuite/core/FileBasedPackageNameProvider.java
+++ /dev/null
@@ -1,60 +0,0 @@
-/*
- * Copyright (C) 2021 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.csuite.core;
-
-import com.android.tradefed.config.Option;
-
-import com.google.common.annotations.VisibleForTesting;
-
-import java.io.File;
-import java.io.IOException;
-import java.nio.file.Files;
-import java.util.HashSet;
-import java.util.Set;
-import java.util.stream.Collectors;
-
-/** A package name provider that accepts files that contains package names. */
-public final class FileBasedPackageNameProvider implements PackageNameProvider {
-    @VisibleForTesting static final String PACKAGES_FILE = "packages-file";
-    @VisibleForTesting static final String COMMENT_LINE_PREFIX = "#";
-
-    @Option(
-            name = PACKAGES_FILE,
-            description =
-                    "File paths that contain package names separated by newline characters."
-                        + " Comment lines are supported only if the lines start with double slash."
-                        + " Trailing comments are not supported. Empty lines are ignored.")
-    private final Set<File> mPackagesFiles = new HashSet<>();
-
-    @Override
-    public Set<String> get() throws IOException {
-        Set<String> packages = new HashSet<>();
-        for (File packagesFile : mPackagesFiles) {
-            packages.addAll(
-                    Files.readAllLines(packagesFile.toPath()).parallelStream()
-                            .map(String::trim)
-                            .filter(this::isPackageName)
-                            .collect(Collectors.toSet()));
-        }
-        return packages;
-    }
-
-    private boolean isPackageName(String text) {
-        // Check the text is not an empty string and not a comment line.
-        return !text.isEmpty() && !text.startsWith(COMMENT_LINE_PREFIX);
-    }
-}
diff --git a/harness/src/main/java/com/android/csuite/core/ModuleGenerator.java b/harness/src/main/java/com/android/csuite/core/ModuleGenerator.java
new file mode 100644
index 0000000..2bc62cf
--- /dev/null
+++ b/harness/src/main/java/com/android/csuite/core/ModuleGenerator.java
@@ -0,0 +1,220 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.csuite.core;
+
+import com.android.compatibility.common.tradefed.build.CompatibilityBuildHelper;
+import com.android.tradefed.build.IBuildInfo;
+import com.android.tradefed.config.IConfiguration;
+import com.android.tradefed.config.IConfigurationReceiver;
+import com.android.tradefed.device.DeviceNotAvailableException;
+import com.android.tradefed.invoker.TestInformation;
+import com.android.tradefed.result.ITestInvocationListener;
+import com.android.tradefed.targetprep.ITargetPreparer;
+import com.android.tradefed.testtype.IBuildReceiver;
+import com.android.tradefed.testtype.IRemoteTest;
+import com.android.tradefed.testtype.IShardableTest;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.errorprone.annotations.MustBeClosed;
+
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.stream.Stream;
+
+/**
+ * Generates TradeFed suite modules during runtime.
+ *
+ * <p>This class generates module config files into TradeFed's test directory at runtime using a
+ * template. Since the content of the test directory relies on what is being generated in a test
+ * run, there can only be one instance executing at a given time.
+ *
+ * <p>The intention of this class is to generate test modules at the beginning of a test run and
+ * cleans up after all tests finish, which resembles a target preparer. However, a target preparer
+ * is executed after the sharding process has finished. The only way to make the generated modules
+ * available for sharding without making changes to TradeFed's core code is to disguise this module
+ * generator as an instance of IShardableTest and declare it separately in test plan config. This is
+ * hacky, and in the long term a TradeFed centered solution is desired. For more details, see
+ * go/sharding-hack-for-module-gen. Note that since the generate step is executed as a test instance
+ * and cleanup step is executed as a target preparer, there should be no saved states between
+ * generating and cleaning up module files.
+ *
+ * <p>This module generator collects modules' info from all ModuleInfoProvider objects specified in
+ * the test plan config.
+ *
+ * <h2>Syntax and usage</h2>
+ *
+ * <p>References to module info providers in TradeFed test plan config must have the following
+ * syntax:
+ *
+ * <blockquote>
+ *
+ * <b>&lt;object type="MODULE_INFO_PROVIDER" class="</b><i>provider_class_name</i><b>"/&gt;</b>
+ *
+ * </blockquote>
+ *
+ * where <i>provider_class_name</i> is the fully-qualified class name of an ModuleInfoProvider
+ * implementation class.
+ */
+public final class ModuleGenerator
+        implements IRemoteTest,
+                IShardableTest,
+                IBuildReceiver,
+                IConfigurationReceiver,
+                ITargetPreparer {
+    @VisibleForTesting static final String MODULE_FILE_NAME_EXTENSION = ".config";
+    @VisibleForTesting static final String MODULE_INFO_PROVIDER = "MODULE_INFO_PROVIDER";
+    private static final Collection<IRemoteTest> NOT_SPLITTABLE = null;
+
+    private final TestDirectoryProvider mTestDirectoryProvider;
+    private IBuildInfo mBuildInfo;
+    private IConfiguration mConfiguration;
+
+    public ModuleGenerator() {
+        this(buildInfo -> new CompatibilityBuildHelper(buildInfo).getTestsDir().toPath());
+    }
+
+    @VisibleForTesting
+    ModuleGenerator(TestDirectoryProvider testDirectoryProvider) {
+        mTestDirectoryProvider = testDirectoryProvider;
+    }
+
+    @Override
+    public void setUp(TestInformation testInfo) {
+        // Do not add cleanup code here as this method is executed after the split method.
+    }
+
+    /**
+     * Cleans up the generated test modules files.
+     *
+     * <p>Note that this method does not execute from the same instance of this class that generates
+     * the modules so be careful when using any class fields.
+     */
+    @Override
+    public void tearDown(TestInformation testInfo, Throwable e) throws DeviceNotAvailableException {
+        // Gets build info from test info as when the class is executed as a ITargetPreparer
+        // preparer, it is not considered as a IBuildReceiver instance.
+        mBuildInfo = testInfo.getBuildInfo();
+
+        try {
+            deleteModuleFiles();
+        } catch (IOException ioException) {
+            throw new UncheckedIOException(ioException);
+        }
+    }
+
+    private void deleteModuleFiles() throws IOException {
+        Files.list(mTestDirectoryProvider.get(mBuildInfo))
+                .filter(Files::isRegularFile)
+                .filter(path -> path.toString().endsWith(MODULE_FILE_NAME_EXTENSION))
+                .forEach(
+                        path -> {
+                            try {
+                                Files.delete(path);
+                            } catch (IOException ioException) {
+                                throw new UncheckedIOException(ioException);
+                            }
+                        });
+    }
+
+    private void generateModules() throws IOException {
+        deleteModuleFiles();
+        try (Stream<ModuleInfoProvider.ModuleInfo> modulesInfo = getModulesInfo()) {
+            Set<String> moduleNames = new HashSet<>();
+            modulesInfo.forEachOrdered(
+                    moduleInfo -> {
+                        String moduleName = moduleInfo.getName().trim();
+                        if (moduleName.isEmpty()) {
+                            throw new IllegalArgumentException("Module name cannot be empty.");
+                        }
+
+                        if (moduleNames.contains(moduleName)) {
+                            throw new IllegalArgumentException(
+                                    "Duplicated module name: " + moduleName);
+                        }
+
+                        try {
+                            Files.write(
+                                    getModulePath(moduleName), moduleInfo.getContent().getBytes());
+                        } catch (IOException e) {
+                            throw new UncheckedIOException(e);
+                        }
+
+                        moduleNames.add(moduleName);
+                    });
+        }
+    }
+
+    @MustBeClosed
+    @SuppressWarnings("MustBeClosedChecker")
+    private Stream<ModuleInfoProvider.ModuleInfo> getModulesInfo() {
+        return mConfiguration.getConfigurationObjectList(MODULE_INFO_PROVIDER).stream()
+                .map(obj -> (ModuleInfoProvider) obj)
+                .flatMap(
+                        info -> {
+                            try {
+                                return info.get();
+                            } catch (IOException ioException) {
+                                throw new UncheckedIOException(ioException);
+                            }
+                        });
+    }
+
+    /**
+     * Generates test modules. Note that the implementation of this method is not related to
+     * sharding in any way.
+     */
+    @Override
+    public Collection<IRemoteTest> split() {
+        try {
+            generateModules();
+        } catch (IOException ioException) {
+            throw new UncheckedIOException(ioException);
+        }
+        return NOT_SPLITTABLE;
+    }
+
+    private Path getModulePath(String moduleName) throws IOException {
+        return mTestDirectoryProvider
+                .get(mBuildInfo)
+                .resolve(moduleName + MODULE_FILE_NAME_EXTENSION);
+    }
+
+    @Override
+    public void run(final TestInformation testInfo, final ITestInvocationListener listener) {
+        // Intentionally left blank since this class is not really a test.
+    }
+
+    @Override
+    public void setBuild(IBuildInfo buildInfo) {
+        mBuildInfo = buildInfo;
+    }
+
+    @Override
+    public void setConfiguration(IConfiguration configuration) {
+        mConfiguration = configuration;
+    }
+
+    @VisibleForTesting
+    interface TestDirectoryProvider {
+        Path get(IBuildInfo buildInfo) throws IOException;
+    }
+}
diff --git a/harness/src/main/java/com/android/csuite/core/PackageNameProvider.java b/harness/src/main/java/com/android/csuite/core/ModuleInfoProvider.java
index 05709a1..7a2c6af 100644
--- a/harness/src/main/java/com/android/csuite/core/PackageNameProvider.java
+++ b/harness/src/main/java/com/android/csuite/core/ModuleInfoProvider.java
@@ -16,16 +16,30 @@
 
 package com.android.csuite.core;
 
+import com.google.errorprone.annotations.MustBeClosed;
+
 import java.io.IOException;
-import java.util.Set;
-
-/** Provides a list of package names. */
-public interface PackageNameProvider {
-    /**
-     * Returns a set of package names.
-     *
-     * @return the package names. An empty set is returned if no package names are to be provided.
-     * @throws IOException if failed to get package names.
-     */
-    Set<String> get() throws IOException;
+import java.util.stream.Stream;
+
+public interface ModuleInfoProvider {
+    final class ModuleInfo {
+        private final String mName;
+        private final String mContent;
+
+        public ModuleInfo(String name, String content) {
+            mName = name;
+            mContent = content;
+        }
+
+        public String getName() {
+            return mName;
+        }
+
+        public String getContent() {
+            return mContent;
+        }
+    }
+
+    @MustBeClosed
+    Stream<ModuleInfo> get() throws IOException;
 }
diff --git a/harness/src/main/java/com/android/csuite/core/ModuleTemplate.java b/harness/src/main/java/com/android/csuite/core/ModuleTemplate.java
new file mode 100644
index 0000000..36331e9
--- /dev/null
+++ b/harness/src/main/java/com/android/csuite/core/ModuleTemplate.java
@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.csuite.core;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.io.Resources;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.util.Map;
+
+public final class ModuleTemplate {
+    private final String mTemplateContent;
+
+    public static ModuleTemplate load(String template, ResourceLoader resourceLoader)
+            throws IOException {
+        return new ModuleTemplate(resourceLoader.load(template));
+    }
+
+    @VisibleForTesting
+    ModuleTemplate(String templateContent) {
+        mTemplateContent = templateContent;
+    }
+
+    public String substitute(Map<String, String> replacementPairs) {
+        return replacementPairs.keySet().stream()
+                .reduce(
+                        mTemplateContent,
+                        (res, placeholder) ->
+                                res.replace(placeholder, replacementPairs.get(placeholder)));
+    }
+
+    public interface ResourceLoader {
+        String load(String resourceName) throws IOException;
+    }
+
+    public static final class ClassResourceLoader implements ResourceLoader {
+        @Override
+        public String load(String resourceName) throws IOException {
+            return Resources.toString(
+                    getClass().getClassLoader().getResource(resourceName), StandardCharsets.UTF_8);
+        }
+    }
+}
diff --git a/harness/src/main/java/com/android/csuite/core/PackageModuleInfoProvider.java b/harness/src/main/java/com/android/csuite/core/PackageModuleInfoProvider.java
new file mode 100644
index 0000000..a33a964
--- /dev/null
+++ b/harness/src/main/java/com/android/csuite/core/PackageModuleInfoProvider.java
@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.csuite.core;
+
+import com.android.csuite.core.ModuleTemplate.ResourceLoader;
+import com.android.tradefed.config.Option;
+import com.android.tradefed.config.Option.Importance;
+
+import com.google.common.annotations.VisibleForTesting;
+
+import java.io.IOException;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+import java.util.stream.Stream;
+
+/** A module info provider that accepts package names and files that contains package names. */
+public final class PackageModuleInfoProvider implements ModuleInfoProvider {
+    @VisibleForTesting static final String PACKAGE = "package";
+    @VisibleForTesting static final String PACKAGE_PLACEHOLDER = "{package}";
+    @VisibleForTesting static final String TEMPLATE = "template";
+
+    @Option(
+            name = TEMPLATE,
+            description = "Module config template resource path.",
+            importance = Importance.ALWAYS)
+    private String mTemplate;
+
+    @Option(name = PACKAGE, description = "App package names.")
+    private final Set<String> mPackages = new HashSet<>();
+
+    private final ResourceLoader mResourceLoader;
+
+    public PackageModuleInfoProvider() {
+        this(new ModuleTemplate.ClassResourceLoader());
+    }
+
+    @VisibleForTesting
+    PackageModuleInfoProvider(ResourceLoader resourceLoader) {
+        mResourceLoader = resourceLoader;
+    }
+
+    @Override
+    public Stream<ModuleInfoProvider.ModuleInfo> get() throws IOException {
+        ModuleTemplate moduleTemplate = ModuleTemplate.load(mTemplate, mResourceLoader);
+
+        return mPackages.stream()
+                .distinct()
+                .map(
+                        packageName ->
+                                new ModuleInfoProvider.ModuleInfo(
+                                        packageName,
+                                        moduleTemplate.substitute(
+                                                Map.of(PACKAGE_PLACEHOLDER, packageName))));
+    }
+}
diff --git a/harness/src/main/java/com/android/csuite/core/PackagesFileModuleInfoProvider.java b/harness/src/main/java/com/android/csuite/core/PackagesFileModuleInfoProvider.java
new file mode 100644
index 0000000..cf1de81
--- /dev/null
+++ b/harness/src/main/java/com/android/csuite/core/PackagesFileModuleInfoProvider.java
@@ -0,0 +1,94 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.csuite.core;
+
+import com.android.csuite.core.ModuleTemplate.ResourceLoader;
+import com.android.tradefed.config.Option;
+import com.android.tradefed.config.Option.Importance;
+
+import com.google.common.annotations.VisibleForTesting;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.nio.file.Files;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+import java.util.stream.Stream;
+
+/** A module info provider that accepts files that contains package names. */
+public final class PackagesFileModuleInfoProvider implements ModuleInfoProvider {
+    @VisibleForTesting static final String PACKAGES_FILE = "packages-file";
+    @VisibleForTesting static final String COMMENT_LINE_PREFIX = "#";
+    @VisibleForTesting static final String PACKAGE_PLACEHOLDER = "{package}";
+    @VisibleForTesting static final String TEMPLATE = "template";
+
+    @Option(
+            name = TEMPLATE,
+            description = "Module config template resource path.",
+            importance = Importance.ALWAYS)
+    private String mTemplate;
+
+    @Option(
+            name = PACKAGES_FILE,
+            description =
+                    "File paths that contain package names separated by newline characters."
+                        + " Comment lines are supported only if the lines start with double slash."
+                        + " Trailing comments are not supported. Empty lines are ignored.")
+    private final Set<File> mPackagesFiles = new HashSet<>();
+
+    private final ResourceLoader mResourceLoader;
+
+    public PackagesFileModuleInfoProvider() {
+        this(new ModuleTemplate.ClassResourceLoader());
+    }
+
+    @VisibleForTesting
+    PackagesFileModuleInfoProvider(ResourceLoader resourceLoader) {
+        mResourceLoader = resourceLoader;
+    }
+
+    @Override
+    public Stream<ModuleInfoProvider.ModuleInfo> get() throws IOException {
+        ModuleTemplate moduleTemplate = ModuleTemplate.load(mTemplate, mResourceLoader);
+
+        return mPackagesFiles.stream()
+                .flatMap(
+                        file -> {
+                            try {
+                                return Files.readAllLines(file.toPath()).stream();
+                            } catch (IOException e) {
+                                throw new UncheckedIOException(e);
+                            }
+                        })
+                .map(String::trim)
+                .filter(PackagesFileModuleInfoProvider::isNotCommentLine)
+                .distinct()
+                .map(
+                        packageName ->
+                                new ModuleInfoProvider.ModuleInfo(
+                                        packageName,
+                                        moduleTemplate.substitute(
+                                                Map.of(PACKAGE_PLACEHOLDER, packageName))));
+    }
+
+    private static boolean isNotCommentLine(String text) {
+        // Check the text is not an empty string and not a comment line.
+        return !text.isEmpty() && !text.startsWith(COMMENT_LINE_PREFIX);
+    }
+}
diff --git a/harness/src/main/resources/config/csuite-base.xml b/harness/src/main/resources/config/csuite-base.xml
index 03e418b..3d39bb3 100644
--- a/harness/src/main/resources/config/csuite-base.xml
+++ b/harness/src/main/resources/config/csuite-base.xml
@@ -31,9 +31,7 @@
   <target_preparer class="com.android.compatibility.targetprep.AppSetupPreparer">
       <option name="test-file-name" value="csuite-launch-instrumentation.apk"/>
   </target_preparer>
-  <!-- Cleans generated module files after test -->
-  <target_preparer class="com.android.csuite.config.ModuleGenerator" />
 
-  <object type="PACKAGE_NAME_PROVIDER" class="com.android.csuite.core.CommandLinePackageNameProvider" />
-  <object type="PACKAGE_NAME_PROVIDER" class="com.android.csuite.core.FileBasedPackageNameProvider" />
+  <object type="MODULE_INFO_PROVIDER" class="com.android.csuite.core.PackageModuleInfoProvider" />
+  <object type="MODULE_INFO_PROVIDER" class="com.android.csuite.core.PackagesFileModuleInfoProvider" />
 </configuration>
diff --git a/harness/src/test/java/com/android/csuite/CSuiteUnitTests.java b/harness/src/test/java/com/android/csuite/CSuiteUnitTests.java
index 6eb1103..485de56 100644
--- a/harness/src/test/java/com/android/csuite/CSuiteUnitTests.java
+++ b/harness/src/test/java/com/android/csuite/CSuiteUnitTests.java
@@ -25,10 +25,11 @@ import org.junit.runners.Suite.SuiteClasses;
     com.android.compatibility.targetprep.CheckGmsPreparerTest.class,
     com.android.compatibility.testtype.AppLaunchTestTest.class,
     com.android.csuite.config.AppRemoteFileResolverTest.class,
-    com.android.csuite.config.ModuleGeneratorTest.class,
-    com.android.csuite.core.CommandLinePackageNameProviderTest.class,
-    com.android.csuite.core.FileBasedPackageNameProviderTest.class,
+    com.android.csuite.core.ModuleGeneratorTest.class,
+    com.android.csuite.core.PackageModuleInfoProviderTest.class,
+    com.android.csuite.core.PackagesFileModuleInfoProviderTest.class,
     com.android.csuite.core.SystemAppUninstallerTest.class,
+    com.android.csuite.core.ModuleTemplateTest.class,
     com.android.csuite.testing.CorrespondencesTest.class,
     com.android.csuite.testing.MoreAssertsTest.class,
 })
diff --git a/harness/src/test/java/com/android/csuite/config/ModuleGeneratorTest.java b/harness/src/test/java/com/android/csuite/config/ModuleGeneratorTest.java
deleted file mode 100644
index a679828..0000000
--- a/harness/src/test/java/com/android/csuite/config/ModuleGeneratorTest.java
+++ /dev/null
@@ -1,321 +0,0 @@
-/*
- * Copyright (C) 2020 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.csuite.config;
-
-import static com.google.common.truth.Truth.assertThat;
-
-import static org.testng.Assert.assertThrows;
-
-import com.android.csuite.core.PackageNameProvider;
-import com.android.tradefed.build.BuildInfo;
-import com.android.tradefed.config.Configuration;
-import com.android.tradefed.config.IConfiguration;
-import com.android.tradefed.config.OptionSetter;
-import com.android.tradefed.device.ITestDevice;
-import com.android.tradefed.invoker.IInvocationContext;
-import com.android.tradefed.invoker.InvocationContext;
-import com.android.tradefed.invoker.TestInformation;
-
-import com.google.common.collect.ArrayListMultimap;
-import com.google.common.collect.ImmutableList;
-import com.google.common.collect.ImmutableSet;
-import com.google.common.collect.ListMultimap;
-import com.google.common.jimfs.Jimfs;
-import com.google.common.truth.IterableSubject;
-import com.google.common.truth.StringSubject;
-
-import org.junit.Test;
-import org.junit.runner.RunWith;
-import org.junit.runners.JUnit4;
-import org.mockito.Mockito;
-
-import java.io.IOException;
-import java.io.UncheckedIOException;
-import java.nio.file.FileSystem;
-import java.nio.file.Files;
-import java.nio.file.Path;
-import java.util.ArrayList;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
-
-@RunWith(JUnit4.class)
-public final class ModuleGeneratorTest {
-    private static final String TEST_PACKAGE_NAME1 = "test.package.name1";
-    private static final String TEST_PACKAGE_NAME2 = "test.package.name2";
-    private static final String PACKAGE_PLACEHOLDER = "{package}";
-    private static final Exception NO_EXCEPTION = null;
-
-    private final FileSystem mFileSystem =
-            Jimfs.newFileSystem(com.google.common.jimfs.Configuration.unix());
-
-    @Test
-    public void tearDown_packageNamesProvided_deletesGeneratedModules() throws Exception {
-        Path testsDir = createTestsDir();
-        ModuleGenerator generator1 =
-                createGeneratorBuilder()
-                        .setTestsDir(testsDir)
-                        .addPackage(TEST_PACKAGE_NAME1)
-                        .addPackage(TEST_PACKAGE_NAME2)
-                        .build();
-        generator1.split();
-        ModuleGenerator generator2 =
-                createGeneratorBuilder()
-                        .setTestsDir(testsDir)
-                        .addPackage(TEST_PACKAGE_NAME1)
-                        .addPackage(TEST_PACKAGE_NAME2)
-                        .build();
-
-        generator2.tearDown(createTestInfo(), NO_EXCEPTION);
-
-        assertThatListDirectory(testsDir).isEmpty();
-    }
-
-    @Test
-    public void tearDown_packageNamesNotProvided_doesNotThrowError() throws Exception {
-        ModuleGenerator generator = createGeneratorBuilder().setTestsDir(createTestsDir()).build();
-        generator.split();
-
-        generator.tearDown(createTestInfo(), NO_EXCEPTION);
-    }
-
-    @Test
-    public void split_packageNameIsEmptyString_throwsError() throws Exception {
-        ModuleGenerator generator = createGeneratorBuilder().addPackage("").build();
-
-        assertThrows(IllegalArgumentException.class, () -> generator.split());
-    }
-
-    @Test
-    public void split_packageNameContainsPlaceholder_throwsError() throws Exception {
-        ModuleGenerator generator =
-                createGeneratorBuilder().addPackage("a" + PACKAGE_PLACEHOLDER + "b").build();
-
-        assertThrows(IllegalArgumentException.class, () -> generator.split());
-    }
-
-    @Test
-    public void split_multiplePackageNameProviders_generateModulesForAll() throws Exception {
-        Path testsDir = createTestsDir();
-        ModuleGenerator generator =
-                createGeneratorBuilder()
-                        .setTestsDir(testsDir)
-                        .addPackageNameProvider(() -> ImmutableSet.of(TEST_PACKAGE_NAME1))
-                        // Simulates package providers providing duplicated package names.
-                        .addPackageNameProvider(() -> ImmutableSet.of(TEST_PACKAGE_NAME1))
-                        .addPackageNameProvider(() -> ImmutableSet.of(TEST_PACKAGE_NAME2))
-                        .build();
-
-        generator.split();
-
-        assertThatListDirectory(testsDir)
-                .containsExactly(
-                        getModuleConfigFile(testsDir, TEST_PACKAGE_NAME1),
-                        getModuleConfigFile(testsDir, TEST_PACKAGE_NAME2));
-    }
-
-    @Test
-    public void split_packageNameProviderThrowsException_throwsException() throws Exception {
-        Path testsDir = createTestsDir();
-        ModuleGenerator generator =
-                createGeneratorBuilder()
-                        .setTestsDir(testsDir)
-                        .addPackageNameProvider(
-                                () -> {
-                                    throw new IOException();
-                                })
-                        .build();
-
-        assertThrows(UncheckedIOException.class, () -> generator.split());
-    }
-
-    @Test
-    public void split_packageNamesNotProvided_doesNotGenerate() throws Exception {
-        Path testsDir = createTestsDir();
-        ModuleGenerator generator = createGeneratorBuilder().setTestsDir(testsDir).build();
-
-        generator.split();
-
-        assertThatListDirectory(testsDir).isEmpty();
-    }
-
-    @Test
-    public void split_templateContainsPlaceholders_replacesPlaceholdersInOutput() throws Exception {
-        Path testsDir = createTestsDir();
-        String content = "hello placeholder%s%s world";
-        ModuleGenerator generator =
-                createGeneratorBuilder()
-                        .setTestsDir(testsDir)
-                        .addPackage(TEST_PACKAGE_NAME1)
-                        .addPackage(TEST_PACKAGE_NAME2)
-                        .setTemplateContent(
-                                String.format(content, PACKAGE_PLACEHOLDER, PACKAGE_PLACEHOLDER))
-                        .build();
-
-        generator.split();
-
-        assertThatModuleConfigFileContent(testsDir, TEST_PACKAGE_NAME1)
-                .isEqualTo(String.format(content, TEST_PACKAGE_NAME1, TEST_PACKAGE_NAME1));
-        assertThatModuleConfigFileContent(testsDir, TEST_PACKAGE_NAME2)
-                .isEqualTo(String.format(content, TEST_PACKAGE_NAME2, TEST_PACKAGE_NAME2));
-    }
-
-    @Test
-    public void split_templateDoesNotContainPlaceholder_outputsTemplateContent() throws Exception {
-        Path testsDir = createTestsDir();
-        String content = "no placeholder";
-        ModuleGenerator generator =
-                createGeneratorBuilder()
-                        .setTestsDir(testsDir)
-                        .addPackage(TEST_PACKAGE_NAME1)
-                        .addPackage(TEST_PACKAGE_NAME2)
-                        .setTemplateContent(content)
-                        .build();
-
-        generator.split();
-
-        assertThatModuleConfigFileContent(testsDir, TEST_PACKAGE_NAME1).isEqualTo(content);
-        assertThatModuleConfigFileContent(testsDir, TEST_PACKAGE_NAME2).isEqualTo(content);
-    }
-
-    @Test
-    public void split_templateContentIsEmpty_outputsTemplateContent() throws Exception {
-        Path testsDir = createTestsDir();
-        String content = "";
-        ModuleGenerator generator =
-                createGeneratorBuilder()
-                        .setTestsDir(testsDir)
-                        .addPackage(TEST_PACKAGE_NAME1)
-                        .addPackage(TEST_PACKAGE_NAME2)
-                        .setTemplateContent(content)
-                        .build();
-
-        generator.split();
-
-        assertThatModuleConfigFileContent(testsDir, TEST_PACKAGE_NAME1).isEqualTo(content);
-        assertThatModuleConfigFileContent(testsDir, TEST_PACKAGE_NAME2).isEqualTo(content);
-    }
-
-    private static StringSubject assertThatModuleConfigFileContent(
-            Path testsDir, String packageName) throws IOException {
-        return assertThat(
-                new String(Files.readAllBytes(getModuleConfigFile(testsDir, packageName))));
-    }
-
-    private static IterableSubject assertThatListDirectory(Path dir) throws IOException {
-        // Convert stream to list because com.google.common.truth.Truth8 is not available.
-        return assertThat(
-                Files.walk(dir)
-                        .filter(p -> !p.equals(dir))
-                        .collect(ImmutableList.toImmutableList()));
-    }
-
-    private static Path getModuleConfigFile(Path baseDir, String packageName) {
-        return baseDir.resolve(packageName + ".config");
-    }
-
-    private Path createTestsDir() throws IOException {
-        Path rootPath = mFileSystem.getPath("csuite");
-        Files.createDirectories(rootPath);
-        return Files.createTempDirectory(rootPath, "testDir");
-    }
-
-    private static TestInformation createTestInfo() {
-        IInvocationContext context = new InvocationContext();
-        context.addAllocatedDevice("device1", Mockito.mock(ITestDevice.class));
-        context.addDeviceBuildInfo("device1", new BuildInfo());
-        return TestInformation.newBuilder().setInvocationContext(context).build();
-    }
-
-    private GeneratorBuilder createGeneratorBuilder() throws IOException {
-        return new GeneratorBuilder()
-                .setFileSystem(mFileSystem)
-                .setTemplateContent(MODULE_TEMPLATE_CONTENT)
-                .setOption(ModuleGenerator.OPTION_TEMPLATE, "empty_path");
-    }
-
-    private static final class GeneratorBuilder {
-        private final ListMultimap<String, String> mOptions = ArrayListMultimap.create();
-        private final Set<String> mPackages = new HashSet<>();
-        private final List<PackageNameProvider> mPackageNameProviders = new ArrayList<>();
-        private Path mTestsDir;
-        private String mTemplateContent;
-        private FileSystem mFileSystem;
-
-        GeneratorBuilder addPackage(String packageName) {
-            mPackages.add(packageName);
-            return this;
-        }
-
-        GeneratorBuilder addPackageNameProvider(PackageNameProvider packageNameProvider) {
-            mPackageNameProviders.add(packageNameProvider);
-            return this;
-        }
-
-        GeneratorBuilder setFileSystem(FileSystem fileSystem) {
-            mFileSystem = fileSystem;
-            return this;
-        }
-
-        GeneratorBuilder setTemplateContent(String templateContent) {
-            mTemplateContent = templateContent;
-            return this;
-        }
-
-        GeneratorBuilder setTestsDir(Path testsDir) {
-            mTestsDir = testsDir;
-            return this;
-        }
-
-        GeneratorBuilder setOption(String key, String value) {
-            mOptions.put(key, value);
-            return this;
-        }
-
-        ModuleGenerator build() throws Exception {
-            ModuleGenerator generator =
-                    new ModuleGenerator(
-                            mFileSystem, buildInfo -> mTestsDir, resourcePath -> mTemplateContent);
-
-            OptionSetter optionSetter = new OptionSetter(generator);
-            for (Map.Entry<String, String> entry : mOptions.entries()) {
-                optionSetter.setOptionValue(entry.getKey(), entry.getValue());
-            }
-
-            List<PackageNameProvider> packageNameProviders = new ArrayList<>(mPackageNameProviders);
-            packageNameProviders.add(() -> mPackages);
-
-            IConfiguration configuration = new Configuration("name", "description");
-            configuration.setConfigurationObjectList(
-                    ModuleGenerator.PACKAGE_NAME_PROVIDER, packageNameProviders);
-            generator.setConfiguration(configuration);
-
-            return generator;
-        }
-    }
-
-    private static final String MODULE_TEMPLATE_CONTENT =
-            "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n"
-                    + "<configuration description=\"description\">\n"
-                    + "    <option name=\"package-name\" value=\"{package}\"/>\n"
-                    + "    <target_generator class=\"some.generator.class\">\n"
-                    + "        <option name=\"test-file-name\" value=\"app://{package}\"/>\n"
-                    + "    </target_generator>\n"
-                    + "    <test class=\"some.test.class\"/>\n"
-                    + "</configuration>";
-}
diff --git a/harness/src/test/java/com/android/csuite/core/CommandLinePackageNameProviderTest.java b/harness/src/test/java/com/android/csuite/core/CommandLinePackageNameProviderTest.java
deleted file mode 100644
index 41e6dc1..0000000
--- a/harness/src/test/java/com/android/csuite/core/CommandLinePackageNameProviderTest.java
+++ /dev/null
@@ -1,45 +0,0 @@
-/*
- * Copyright (C) 2021 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.csuite.core;
-
-import static com.google.common.truth.Truth.assertThat;
-
-import com.android.tradefed.config.OptionSetter;
-
-import org.junit.Test;
-import org.junit.runner.RunWith;
-import org.junit.runners.JUnit4;
-
-import java.util.Set;
-
-@RunWith(JUnit4.class)
-public final class CommandLinePackageNameProviderTest {
-
-    @Test
-    public void get_packageNamesProvided_returnsPackageNames() throws Exception {
-        CommandLinePackageNameProvider provider = new CommandLinePackageNameProvider();
-        String package1 = "package.name1";
-        String package2 = "package.name2";
-        OptionSetter optionSetter = new OptionSetter(provider);
-        optionSetter.setOptionValue(CommandLinePackageNameProvider.PACKAGE, package1);
-        optionSetter.setOptionValue(CommandLinePackageNameProvider.PACKAGE, package2);
-
-        Set<String> packageNames = provider.get();
-
-        assertThat(packageNames).containsExactly(package1, package2);
-    }
-}
diff --git a/harness/src/test/java/com/android/csuite/core/FileBasedPackageNameProviderTest.java b/harness/src/test/java/com/android/csuite/core/FileBasedPackageNameProviderTest.java
deleted file mode 100644
index ee429b2..0000000
--- a/harness/src/test/java/com/android/csuite/core/FileBasedPackageNameProviderTest.java
+++ /dev/null
@@ -1,116 +0,0 @@
-/*
- * Copyright (C) 2020 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.csuite.core;
-
-import static com.google.common.truth.Truth.assertThat;
-
-import com.android.tradefed.config.ConfigurationException;
-import com.android.tradefed.config.OptionSetter;
-
-import org.junit.Rule;
-import org.junit.Test;
-import org.junit.rules.TemporaryFolder;
-import org.junit.runner.RunWith;
-import org.junit.runners.JUnit4;
-
-import java.io.IOException;
-import java.nio.file.Files;
-import java.nio.file.Path;
-import java.util.Set;
-
-@RunWith(JUnit4.class)
-public final class FileBasedPackageNameProviderTest {
-    private static final String TEST_PACKAGE_NAME1 = "test.package.name1";
-    private static final String TEST_PACKAGE_NAME2 = "test.package.name2";
-    private static final String PACKAGE_PLACEHOLDER = "{package}";
-    private static final Exception NO_EXCEPTION = null;
-
-    @Rule public final TemporaryFolder tempFolder = new TemporaryFolder();
-
-    @Test
-    public void get_fileNotSpecified_returnsEmptySet() throws Exception {
-        FileBasedPackageNameProvider provider = createProvider();
-
-        Set<String> packageNames = provider.get();
-
-        assertThat(packageNames).isEmpty();
-    }
-
-    @Test
-    public void get_multipleFileSpecified_returnsAllEntries() throws Exception {
-        String packageName1 = "a";
-        String packageName2 = "b";
-        String packageName3 = "c";
-        String packageName4 = "d";
-        FileBasedPackageNameProvider provider =
-                createProvider(
-                        createPackagesFile(packageName1 + "\n" + packageName2),
-                        createPackagesFile(packageName3 + "\n" + packageName4));
-
-        Set<String> packageNames = provider.get();
-
-        assertThat(packageNames)
-                .containsExactly(packageName1, packageName2, packageName3, packageName4);
-    }
-
-    @Test
-    public void get_fileContainsEmptyLines_ignoresEmptyLines() throws Exception {
-        String packageName1 = "a";
-        String packageName2 = "b";
-        FileBasedPackageNameProvider provider =
-                createProvider(createPackagesFile(packageName1 + "\n \n\n" + packageName2));
-
-        Set<String> packageNames = provider.get();
-
-        assertThat(packageNames).containsExactly(packageName1, packageName2);
-    }
-
-    @Test
-    public void get_fileContainsCommentLines_ignoresCommentLines() throws Exception {
-        String packageName1 = "a";
-        String packageName2 = "b";
-        FileBasedPackageNameProvider provider =
-                createProvider(
-                        createPackagesFile(
-                                packageName1
-                                        + "\n"
-                                        + FileBasedPackageNameProvider.COMMENT_LINE_PREFIX
-                                        + " Some comments\n"
-                                        + packageName2));
-
-        Set<String> packageNames = provider.get();
-
-        assertThat(packageNames).containsExactly(packageName1, packageName2);
-    }
-
-    private FileBasedPackageNameProvider createProvider(Path... packagesFiles)
-            throws IOException, ConfigurationException {
-        FileBasedPackageNameProvider provider = new FileBasedPackageNameProvider();
-        OptionSetter optionSetter = new OptionSetter(provider);
-        for (Path packagesFile : packagesFiles) {
-            optionSetter.setOptionValue(
-                    FileBasedPackageNameProvider.PACKAGES_FILE, packagesFile.toString());
-        }
-        return provider;
-    }
-
-    private Path createPackagesFile(String content) throws IOException {
-        Path tempFile = Files.createTempFile(tempFolder.getRoot().toPath(), "packages", ".txt");
-        Files.write(tempFile, content.getBytes());
-        return tempFile;
-    }
-}
diff --git a/harness/src/test/java/com/android/csuite/core/ModuleGeneratorTest.java b/harness/src/test/java/com/android/csuite/core/ModuleGeneratorTest.java
new file mode 100644
index 0000000..c785a42
--- /dev/null
+++ b/harness/src/test/java/com/android/csuite/core/ModuleGeneratorTest.java
@@ -0,0 +1,315 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.csuite.core;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import static org.testng.Assert.assertThrows;
+
+import com.android.tradefed.build.BuildInfo;
+import com.android.tradefed.config.Configuration;
+import com.android.tradefed.config.IConfiguration;
+import com.android.tradefed.device.ITestDevice;
+import com.android.tradefed.invoker.IInvocationContext;
+import com.android.tradefed.invoker.InvocationContext;
+import com.android.tradefed.invoker.TestInformation;
+
+import com.google.common.collect.ImmutableList;
+import com.google.common.jimfs.Jimfs;
+import com.google.common.truth.IterableSubject;
+import com.google.common.truth.StringSubject;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+import org.mockito.Mockito;
+
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.nio.file.FileSystem;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.stream.Stream;
+
+@RunWith(JUnit4.class)
+public final class ModuleGeneratorTest {
+    private static final String TEST_PACKAGE_NAME1 = "test.package.name1";
+    private static final String TEST_PACKAGE_NAME2 = "test.package.name2";
+    private static final String TEST_PACKAGE_NAME3 = "test.package.name3";
+    private static final String PACKAGE_PLACEHOLDER = "{package}";
+    private static final Exception NO_EXCEPTION = null;
+
+    private final FileSystem mFileSystem =
+            Jimfs.newFileSystem(com.google.common.jimfs.Configuration.unix());
+
+    @Test
+    public void tearDown_nonModuleFilesExist_doesNotDeleteNonModules() throws Exception {
+        Path testsDir = createTestsDir();
+        Path nonModule = Files.createFile(testsDir.resolve("a"));
+        Files.createFile(testsDir.resolve("b" + ModuleGenerator.MODULE_FILE_NAME_EXTENSION));
+        ModuleGenerator generator = new GeneratorBuilder().setTestsDir(testsDir).build();
+
+        generator.tearDown(createTestInfo(), NO_EXCEPTION);
+
+        assertThatListDirectory(testsDir).containsExactly(nonModule);
+    }
+
+    @Test
+    public void tearDown_packageNamesProvided_deletesGeneratedModules() throws Exception {
+        Path testsDir = createTestsDir();
+        ModuleGenerator generator1 =
+                new GeneratorBuilder()
+                        .setTestsDir(testsDir)
+                        .addModuleInfoProvider(
+                                () ->
+                                        Stream.of(
+                                                new ModuleInfoProvider.ModuleInfo(
+                                                        TEST_PACKAGE_NAME1, "")))
+                        .addModuleInfoProvider(
+                                () ->
+                                        Stream.of(
+                                                new ModuleInfoProvider.ModuleInfo(
+                                                        TEST_PACKAGE_NAME2, "")))
+                        .build();
+        generator1.split();
+        ModuleGenerator generator2 = new GeneratorBuilder().setTestsDir(testsDir).build();
+
+        generator2.tearDown(createTestInfo(), NO_EXCEPTION);
+
+        assertThatListDirectory(testsDir).isEmpty();
+    }
+
+    @Test
+    public void tearDown_moduleInfoNotProvided_doesNotThrowError() throws Exception {
+        ModuleGenerator generator = new GeneratorBuilder().setTestsDir(createTestsDir()).build();
+        generator.split();
+
+        generator.tearDown(createTestInfo(), NO_EXCEPTION);
+    }
+
+    @Test
+    public void split_moduleInfoStreamProvided_streamIsClosed() throws Exception {
+        AtomicBoolean wasClosed = new AtomicBoolean(false);
+        ModuleGenerator generator =
+                new GeneratorBuilder()
+                        .setTestsDir(createTestsDir())
+                        .addModuleInfoProvider(
+                                () ->
+                                        Stream.of(
+                                                        new ModuleInfoProvider.ModuleInfo(
+                                                                TEST_PACKAGE_NAME1, ""))
+                                                .onClose(() -> wasClosed.set(true)))
+                        .build();
+
+        generator.split();
+
+        assertThat(wasClosed.get()).isTrue();
+    }
+
+    @Test
+    public void split_moduleInfoProvidersSpecified_contentIsWritten() throws Exception {
+        Path testsDir = createTestsDir();
+        String content1 = "a";
+        String content2 = "b";
+        ModuleGenerator generator =
+                new GeneratorBuilder()
+                        .setTestsDir(testsDir)
+                        .addModuleInfoProvider(
+                                () ->
+                                        Stream.of(
+                                                new ModuleInfoProvider.ModuleInfo(
+                                                        TEST_PACKAGE_NAME1, content1)))
+                        .addModuleInfoProvider(
+                                () ->
+                                        Stream.of(
+                                                new ModuleInfoProvider.ModuleInfo(
+                                                        TEST_PACKAGE_NAME2, content2)))
+                        .build();
+
+        generator.split();
+
+        assertThatModuleConfigFileContent(testsDir, TEST_PACKAGE_NAME1).isEqualTo(content1);
+        assertThatModuleConfigFileContent(testsDir, TEST_PACKAGE_NAME2).isEqualTo(content2);
+    }
+
+    @Test
+    public void split_emptyModuleNameProvided_throwsException() throws Exception {
+        Path testsDir = createTestsDir();
+        ModuleGenerator generator =
+                new GeneratorBuilder()
+                        .setTestsDir(testsDir)
+                        .addModuleInfoProvider(
+                                () -> Stream.of(new ModuleInfoProvider.ModuleInfo(" ", "a")))
+                        .build();
+
+        assertThrows(IllegalArgumentException.class, () -> generator.split());
+    }
+
+    @Test
+    public void split_duplicatedModuleNamesProvided_throwsException() throws Exception {
+        Path testsDir = createTestsDir();
+        ModuleGenerator generator =
+                new GeneratorBuilder()
+                        .setTestsDir(testsDir)
+                        .addModuleInfoProvider(
+                                () ->
+                                        Stream.of(
+                                                new ModuleInfoProvider.ModuleInfo(
+                                                        TEST_PACKAGE_NAME1, "a")))
+                        .addModuleInfoProvider(
+                                () ->
+                                        Stream.of(
+                                                new ModuleInfoProvider.ModuleInfo(
+                                                        TEST_PACKAGE_NAME1, "b")))
+                        .build();
+
+        assertThrows(IllegalArgumentException.class, () -> generator.split());
+    }
+
+    @Test
+    public void split_moduleInfoProvidersSpecified_generateModulesForAll() throws Exception {
+        Path testsDir = createTestsDir();
+        ModuleGenerator generator =
+                new GeneratorBuilder()
+                        .setTestsDir(testsDir)
+                        .addModuleInfoProvider(
+                                () ->
+                                        Arrays.asList(
+                                                new ModuleInfoProvider.ModuleInfo(
+                                                        TEST_PACKAGE_NAME1, ""),
+                                                new ModuleInfoProvider.ModuleInfo(
+                                                        TEST_PACKAGE_NAME2, ""))
+                                                .stream())
+                        .addModuleInfoProvider(
+                                () ->
+                                        Stream.of(
+                                                new ModuleInfoProvider.ModuleInfo(
+                                                        TEST_PACKAGE_NAME3, "")))
+                        .build();
+
+        generator.split();
+
+        assertThatListDirectory(testsDir)
+                .containsExactly(
+                        getModuleConfigFile(testsDir, TEST_PACKAGE_NAME1),
+                        getModuleConfigFile(testsDir, TEST_PACKAGE_NAME2),
+                        getModuleConfigFile(testsDir, TEST_PACKAGE_NAME3));
+    }
+
+    @Test
+    public void split_streamThrowsException_throwsException() throws Exception {
+        ModuleGenerator generator =
+                new GeneratorBuilder()
+                        .setTestsDir(createTestsDir())
+                        .addModuleInfoProvider(
+                                () ->
+                                        Arrays.stream(new String[] {"a"})
+                                                .map(
+                                                        i -> {
+                                                            throw new UncheckedIOException(
+                                                                    new IOException());
+                                                        }))
+                        .build();
+
+        assertThrows(UncheckedIOException.class, () -> generator.split());
+    }
+
+    @Test
+    public void split_providerThrowsException_throwsException() throws Exception {
+        ModuleGenerator generator =
+                new GeneratorBuilder()
+                        .setTestsDir(createTestsDir())
+                        .addModuleInfoProvider(
+                                () -> {
+                                    throw new UncheckedIOException(new IOException());
+                                })
+                        .build();
+
+        assertThrows(UncheckedIOException.class, () -> generator.split());
+    }
+
+    @Test
+    public void split_noProviders_doesNotGenerate() throws Exception {
+        Path testsDir = createTestsDir();
+        ModuleGenerator generator = new GeneratorBuilder().setTestsDir(testsDir).build();
+
+        generator.split();
+
+        assertThatListDirectory(testsDir).isEmpty();
+    }
+
+    private static StringSubject assertThatModuleConfigFileContent(
+            Path testsDir, String packageName) throws IOException {
+        return assertThat(
+                new String(Files.readAllBytes(getModuleConfigFile(testsDir, packageName))));
+    }
+
+    private static IterableSubject assertThatListDirectory(Path dir) throws IOException {
+        // Convert stream to list because com.google.common.truth.Truth8 is not available.
+        return assertThat(
+                Files.walk(dir)
+                        .filter(p -> !p.equals(dir))
+                        .collect(ImmutableList.toImmutableList()));
+    }
+
+    private static Path getModuleConfigFile(Path baseDir, String packageName) {
+        return baseDir.resolve(packageName + ".config");
+    }
+
+    private Path createTestsDir() throws IOException {
+        Path rootPath = mFileSystem.getPath("csuite");
+        Files.createDirectories(rootPath);
+        return Files.createTempDirectory(rootPath, "testDir");
+    }
+
+    private static final class GeneratorBuilder {
+        private final List<ModuleInfoProvider> mModuleInfoProviders = new ArrayList<>();
+        private Path mTestsDir;
+
+        GeneratorBuilder addModuleInfoProvider(ModuleInfoProvider moduleInfoProviders) {
+            mModuleInfoProviders.add(moduleInfoProviders);
+            return this;
+        }
+
+        GeneratorBuilder setTestsDir(Path testsDir) {
+            mTestsDir = testsDir;
+            return this;
+        }
+
+        ModuleGenerator build() throws Exception {
+            ModuleGenerator generator = new ModuleGenerator(buildInfo -> mTestsDir);
+
+            IConfiguration configuration = new Configuration("name", "description");
+            configuration.setConfigurationObjectList(
+                    ModuleGenerator.MODULE_INFO_PROVIDER, mModuleInfoProviders);
+            generator.setConfiguration(configuration);
+
+            return generator;
+        }
+    }
+
+    private static TestInformation createTestInfo() {
+        IInvocationContext context = new InvocationContext();
+        context.addAllocatedDevice("device1", Mockito.mock(ITestDevice.class));
+        context.addDeviceBuildInfo("device1", new BuildInfo());
+        return TestInformation.newBuilder().setInvocationContext(context).build();
+    }
+}
diff --git a/harness/src/test/java/com/android/csuite/core/ModuleTemplateTest.java b/harness/src/test/java/com/android/csuite/core/ModuleTemplateTest.java
new file mode 100644
index 0000000..2d7c700
--- /dev/null
+++ b/harness/src/test/java/com/android/csuite/core/ModuleTemplateTest.java
@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.csuite.core;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+import java.util.Map;
+
+@RunWith(JUnit4.class)
+public final class ModuleTemplateTest {
+    @Test
+    public void substitute_multipleReplacementPairs_replaceAll() throws Exception {
+        String template = "-ab";
+        ModuleTemplate subject = createTestSubject(template);
+
+        String content = subject.substitute(Map.of("a", "c", "b", "d"));
+
+        assertThat(content).isEqualTo("-cd");
+    }
+
+    @Test
+    public void substitute_replacementKeyNotInTemplate_doesNotReplace() throws Exception {
+        String template = "-a";
+        ModuleTemplate subject = createTestSubject(template);
+
+        String content = subject.substitute(Map.of("b", ""));
+
+        assertThat(content).isEqualTo(template);
+    }
+
+    @Test
+    public void substitute_multipleReplacementKeyInTemplate_replaceTheKeys() throws Exception {
+        String template = "-aba";
+        ModuleTemplate subject = createTestSubject(template);
+
+        String content = subject.substitute(Map.of("a", "c"));
+
+        assertThat(content).isEqualTo("-cbc");
+    }
+
+    @Test
+    public void substitute_noReplacementPairs_returnTemplate() throws Exception {
+        String template = "-a";
+        ModuleTemplate subject = createTestSubject(template);
+
+        String content = subject.substitute(Map.of());
+
+        assertThat(content).isEqualTo(template);
+    }
+
+    @Test
+    public void substitute_templateContentIsEmpty_returnEmptyString() throws Exception {
+        String template = "";
+        ModuleTemplate subject = createTestSubject(template);
+
+        String content = subject.substitute(Map.of("a", "b"));
+
+        assertThat(content).isEqualTo(template);
+    }
+
+    private static ModuleTemplate createTestSubject(String templateContent) {
+        return new ModuleTemplate(templateContent);
+    }
+}
diff --git a/harness/src/test/java/com/android/csuite/core/PackageModuleInfoProviderTest.java b/harness/src/test/java/com/android/csuite/core/PackageModuleInfoProviderTest.java
new file mode 100644
index 0000000..754f4a2
--- /dev/null
+++ b/harness/src/test/java/com/android/csuite/core/PackageModuleInfoProviderTest.java
@@ -0,0 +1,142 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.csuite.core;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.android.tradefed.config.OptionSetter;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+@RunWith(JUnit4.class)
+public final class PackageModuleInfoProviderTest {
+    @Rule public final TemporaryFolder tempFolder = new TemporaryFolder();
+
+    @Test
+    public void get_templateContainsPlaceholders_replacesPlaceholdersInOutput() throws Exception {
+        String content = "hello placeholder%s%s world";
+        String packageName1 = "a";
+        String packageName2 = "b";
+        PackageModuleInfoProvider provider =
+                createProviderBuilder()
+                        .addPackage(packageName1)
+                        .addPackage(packageName2)
+                        .setTemplateContent(
+                                String.format(
+                                        content,
+                                        PackagesFileModuleInfoProvider.PACKAGE_PLACEHOLDER,
+                                        PackagesFileModuleInfoProvider.PACKAGE_PLACEHOLDER))
+                        .build();
+
+        Stream<ModuleInfoProvider.ModuleInfo> modulesInfo = provider.get();
+
+        assertThat(collectModuleContentStrings(modulesInfo))
+                .containsExactly(
+                        String.format(content, packageName1, packageName1),
+                        String.format(content, packageName2, packageName2));
+    }
+
+    @Test
+    public void get_containsDuplicatedPackageNames_ignoreDuplicates() throws Exception {
+        String packageName1 = "a";
+        String packageName2 = "b";
+        PackageModuleInfoProvider provider =
+                createProviderBuilder()
+                        .addPackage(packageName1)
+                        .addPackage(packageName1)
+                        .addPackage(packageName2)
+                        .build();
+
+        Stream<ModuleInfoProvider.ModuleInfo> modulesInfo = provider.get();
+
+        assertThat(collectModuleNames(modulesInfo)).containsExactly(packageName1, packageName2);
+    }
+
+    @Test
+    public void get_packageNamesProvided_returnsPackageNames() throws Exception {
+        String packageName1 = "a";
+        String packageName2 = "b";
+        PackageModuleInfoProvider provider =
+                createProviderBuilder().addPackage(packageName1).addPackage(packageName2).build();
+
+        Stream<ModuleInfoProvider.ModuleInfo> modulesInfo = provider.get();
+
+        assertThat(collectModuleNames(modulesInfo)).containsExactly(packageName1, packageName2);
+    }
+
+    private List<String> collectModuleContentStrings(
+            Stream<ModuleInfoProvider.ModuleInfo> modulesInfo) {
+        return modulesInfo
+                .map(ModuleInfoProvider.ModuleInfo::getContent)
+                .collect(Collectors.toList());
+    }
+
+    private List<String> collectModuleNames(Stream<ModuleInfoProvider.ModuleInfo> modulesInfo) {
+        return modulesInfo.map(ModuleInfoProvider.ModuleInfo::getName).collect(Collectors.toList());
+    }
+
+    private ProviderBuilder createProviderBuilder() {
+        return new ProviderBuilder().setTemplateContent(MODULE_TEMPLATE_CONTENT);
+    }
+
+    private static final class ProviderBuilder {
+        private final Set<String> mPackages = new HashSet<>();
+        private String mTemplateContent;
+
+        ProviderBuilder addPackage(String packageName) {
+            mPackages.add(packageName);
+            return this;
+        }
+
+        ProviderBuilder setTemplateContent(String templateContent) {
+            mTemplateContent = templateContent;
+            return this;
+        }
+
+        PackageModuleInfoProvider build() throws Exception {
+            PackageModuleInfoProvider provider =
+                    new PackageModuleInfoProvider(resource -> mTemplateContent);
+
+            OptionSetter optionSetter = new OptionSetter(provider);
+            for (String p : mPackages) {
+                optionSetter.setOptionValue(PackageModuleInfoProvider.PACKAGE, p);
+            }
+            optionSetter.setOptionValue(PackageModuleInfoProvider.TEMPLATE, "empty");
+            return provider;
+        }
+    }
+
+    private static final String MODULE_TEMPLATE_CONTENT =
+            "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n"
+                    + "<configuration description=\"description\">\n"
+                    + "    <option name=\"package-name\" value=\"{package}\"/>\n"
+                    + "    <target_generator class=\"some.generator.class\">\n"
+                    + "        <option name=\"test-file-name\" value=\"app://{package}\"/>\n"
+                    + "    </target_generator>\n"
+                    + "    <test class=\"some.test.class\"/>\n"
+                    + "</configuration>";
+}
diff --git a/harness/src/test/java/com/android/csuite/core/PackagesFileModuleInfoProviderTest.java b/harness/src/test/java/com/android/csuite/core/PackagesFileModuleInfoProviderTest.java
new file mode 100644
index 0000000..12ea012
--- /dev/null
+++ b/harness/src/test/java/com/android/csuite/core/PackagesFileModuleInfoProviderTest.java
@@ -0,0 +1,200 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.csuite.core;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.android.tradefed.config.OptionSetter;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+@RunWith(JUnit4.class)
+public final class PackagesFileModuleInfoProviderTest {
+    @Rule public final TemporaryFolder tempFolder = new TemporaryFolder();
+
+    @Test
+    public void get_templateContainsPlaceholders_replacesPlaceholdersInOutput() throws Exception {
+        String content = "hello placeholder%s%s world";
+        String packageName1 = "a";
+        String packageName2 = "b";
+        PackagesFileModuleInfoProvider provider =
+                createProviderBuilder()
+                        .addPackagesFile(createPackagesFile(packageName1 + "\n" + packageName2))
+                        .setTemplateContent(
+                                String.format(
+                                        content,
+                                        PackagesFileModuleInfoProvider.PACKAGE_PLACEHOLDER,
+                                        PackagesFileModuleInfoProvider.PACKAGE_PLACEHOLDER))
+                        .build();
+
+        Stream<ModuleInfoProvider.ModuleInfo> modulesInfo = provider.get();
+
+        assertThat(collectModuleContentStrings(modulesInfo))
+                .containsExactly(
+                        String.format(content, packageName1, packageName1),
+                        String.format(content, packageName2, packageName2));
+    }
+
+    @Test
+    public void get_containsDuplicatedPackageNames_ignoreDuplicates() throws Exception {
+        String packageName1 = "a";
+        String packageName2 = "b";
+        PackagesFileModuleInfoProvider provider =
+                createProviderBuilder()
+                        .addPackagesFile(createPackagesFile(packageName1 + "\n" + packageName1))
+                        .addPackagesFile(createPackagesFile(packageName1 + "\n" + packageName2))
+                        .build();
+
+        Stream<ModuleInfoProvider.ModuleInfo> modulesInfo = provider.get();
+
+        assertThat(collectModuleNames(modulesInfo)).containsExactly(packageName1, packageName2);
+    }
+
+    @Test
+    public void get_fileNotSpecified_returnsEmptySet() throws Exception {
+        PackagesFileModuleInfoProvider provider = createProviderBuilder().build();
+
+        Stream<ModuleInfoProvider.ModuleInfo> modulesInfo = provider.get();
+
+        assertThat(collectModuleNames(modulesInfo)).isEmpty();
+    }
+
+    @Test
+    public void get_multipleFileSpecified_returnsAllEntries() throws Exception {
+        String packageName1 = "a";
+        String packageName2 = "b";
+        String packageName3 = "c";
+        String packageName4 = "d";
+        PackagesFileModuleInfoProvider provider =
+                createProviderBuilder()
+                        .addPackagesFile(createPackagesFile(packageName1 + "\n" + packageName2))
+                        .addPackagesFile(createPackagesFile(packageName3 + "\n" + packageName4))
+                        .build();
+
+        Stream<ModuleInfoProvider.ModuleInfo> modulesInfo = provider.get();
+
+        assertThat(collectModuleNames(modulesInfo))
+                .containsExactly(packageName1, packageName2, packageName3, packageName4);
+    }
+
+    @Test
+    public void get_fileContainsEmptyLines_ignoresEmptyLines() throws Exception {
+        String packageName1 = "a";
+        String packageName2 = "b";
+        PackagesFileModuleInfoProvider provider =
+                createProviderBuilder()
+                        .addPackagesFile(
+                                createPackagesFile(packageName1 + "\n \n\n" + packageName2))
+                        .build();
+
+        Stream<ModuleInfoProvider.ModuleInfo> modulesInfo = provider.get();
+
+        assertThat(collectModuleNames(modulesInfo)).containsExactly(packageName1, packageName2);
+    }
+
+    @Test
+    public void get_fileContainsCommentLines_ignoresCommentLines() throws Exception {
+        String packageName1 = "a";
+        String packageName2 = "b";
+        PackagesFileModuleInfoProvider provider =
+                createProviderBuilder()
+                        .addPackagesFile(
+                                createPackagesFile(
+                                        packageName1
+                                                + "\n"
+                                                + PackagesFileModuleInfoProvider.COMMENT_LINE_PREFIX
+                                                + " Some comments\n"
+                                                + packageName2))
+                        .build();
+
+        Stream<ModuleInfoProvider.ModuleInfo> modulesInfo = provider.get();
+
+        assertThat(collectModuleNames(modulesInfo)).containsExactly(packageName1, packageName2);
+    }
+
+    private List<String> collectModuleContentStrings(
+            Stream<ModuleInfoProvider.ModuleInfo> modulesInfo) {
+        return modulesInfo
+                .map(ModuleInfoProvider.ModuleInfo::getContent)
+                .collect(Collectors.toList());
+    }
+
+    private List<String> collectModuleNames(Stream<ModuleInfoProvider.ModuleInfo> modulesInfo) {
+        return modulesInfo.map(ModuleInfoProvider.ModuleInfo::getName).collect(Collectors.toList());
+    }
+
+    private Path createPackagesFile(String content) throws IOException {
+        Path tempFile = Files.createTempFile(tempFolder.getRoot().toPath(), "packages", ".txt");
+        Files.write(tempFile, content.getBytes());
+        return tempFile;
+    }
+
+    private ProviderBuilder createProviderBuilder() {
+        return new ProviderBuilder().setTemplateContent(MODULE_TEMPLATE_CONTENT);
+    }
+
+    private static final class ProviderBuilder {
+        private final Set<Path> mPackagesFiles = new HashSet<>();
+        private String mTemplateContent;
+
+        ProviderBuilder addPackagesFile(Path packagesFile) {
+            mPackagesFiles.add(packagesFile);
+            return this;
+        }
+
+        ProviderBuilder setTemplateContent(String templateContent) {
+            mTemplateContent = templateContent;
+            return this;
+        }
+
+        PackagesFileModuleInfoProvider build() throws Exception {
+            PackagesFileModuleInfoProvider provider =
+                    new PackagesFileModuleInfoProvider(resource -> mTemplateContent);
+
+            OptionSetter optionSetter = new OptionSetter(provider);
+            for (Path p : mPackagesFiles) {
+                optionSetter.setOptionValue(
+                        PackagesFileModuleInfoProvider.PACKAGES_FILE, p.toString());
+            }
+            optionSetter.setOptionValue(PackagesFileModuleInfoProvider.TEMPLATE, "empty");
+            return provider;
+        }
+    }
+
+    private static final String MODULE_TEMPLATE_CONTENT =
+            "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n"
+                    + "<configuration description=\"description\">\n"
+                    + "    <option name=\"package-name\" value=\"{package}\"/>\n"
+                    + "    <target_generator class=\"some.generator.class\">\n"
+                    + "        <option name=\"test-file-name\" value=\"app://{package}\"/>\n"
+                    + "    </target_generator>\n"
+                    + "    <test class=\"some.test.class\"/>\n"
+                    + "</configuration>";
+}
diff --git a/tools/csuite_test/csuite_test.go b/tools/csuite_test/csuite_test.go
index 74373f2..11469df 100644
--- a/tools/csuite_test/csuite_test.go
+++ b/tools/csuite_test/csuite_test.go
@@ -121,9 +121,13 @@ const (
      limitations under the License.
 -->
 <configuration>
-     <test class="com.android.csuite.config.ModuleGenerator">
-          <option name="template" value="{templatePath}" />
-     </test>
+     <option name="template" value="{templatePath}" />
+
+     <!-- Generates module files in the beginning of the test. -->
+     <test class="com.android.csuite.core.ModuleGenerator" />
+     <!-- Cleans the generated module files after the test. -->
+     <target_preparer class="com.android.csuite.core.ModuleGenerator" />
+
      <include name="csuite-base" />
      <include name="{planInclude}" />
      <option name="plan" value="{planName}" />