Add Google-style ReadFileToString and WriteStringToFile.

Bug: 19217569
Change-Id: I64789d3fa6777ee30a324cdf00fdc275c1230e1b

1 files changed, 37 insertions, 0 deletions

diff --git a/libutils/tests/file_test.cpp b/libutils/tests/file_test.cpp
new file mode 100644
index 000000000..acf66a69f
--- /dev/null
+++ b/libutils/tests/file_test.cpp
@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2013 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.
+ */
+
+#include "utils/file.h"
+
+#include <errno.h>
+#include <gtest/gtest.h>
+
+TEST(file, ReadFileToString_ENOENT) {
+  std::string s("hello");
+  errno = 0;
+  EXPECT_FALSE(android::ReadFileToString("/proc/does-not-exist", &s));
+  EXPECT_EQ(ENOENT, errno);
+  EXPECT_EQ("", s); // s was cleared.
+}
+
+TEST(file, ReadFileToString_success) {
+  std::string s("hello");
+  EXPECT_TRUE(android::ReadFileToString("/proc/version", &s));
+  EXPECT_GT(s.length(), 6U);
+  EXPECT_EQ('\n', s[s.length() - 1]);
+  s[5] = 0;
+  EXPECT_STREQ("Linux", s.c_str());
+}