Creating RankedComparator and using it to sort accounts.

Order of the accounts returned by MailAppProvider can
change even if list of the accounts doesn't change.
This cl should force the accounts to be ordered by
R.array.account_providers and then by order returned by
individual provider.

b/17339644

Change-Id: I7329a9e509a97573c04d3b407dc43ae74118325e

1 files changed, 100 insertions, 0 deletions

diff --git a/tests/src/com/android/mail/utils/RankedComparatorTest.java b/tests/src/com/android/mail/utils/RankedComparatorTest.java
new file mode 100644
index 000000000..85e5cd008
--- /dev/null
+++ b/tests/src/com/android/mail/utils/RankedComparatorTest.java
@@ -0,0 +1,100 @@
+/**
+ * Copyright (C) 2014 Google Inc.
+ * Licensed to 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.mail.utils;
+
+import android.test.AndroidTestCase;
+import android.test.suitebuilder.annotation.SmallTest;
+
+import com.google.android.mail.common.base.Function;
+
+@SmallTest
+public class RankedComparatorTest extends AndroidTestCase {
+
+    private static final String RANK1 = "rank1";
+    private static final String RANK2 = "rank2";
+    private static final String[] RANKS = new String[]{RANK1, RANK2};
+    private static final String UNKNOWN_RANK1 = "unknown_rank_1";
+    private static final String UNKNOWN_RANK2 = "unknown_rank_2";
+    private static final String NULL_RANK = null;
+
+    private RankedComparator<DummyObject, String> comparator;
+
+    @Override
+    protected void setUp() throws Exception {
+        super.setUp();
+        comparator =
+                new RankedComparator<DummyObject, String>(RANKS, DUMMY_OBJECT_TO_RANK_FUNCTION);
+    }
+
+    public void testSimple() {
+        DummyObject rank1_1 = new DummyObject(RANK1);
+        DummyObject rank1_2 = new DummyObject(RANK1);
+        DummyObject rank2 = new DummyObject(RANK2);
+
+        assertTrue("Same object should be equal to itself.",
+                comparator.compare(rank1_1, rank1_1) == 0);
+        assertTrue("Different objects with same rank should be equal.",
+                comparator.compare(rank1_1, rank1_2) == 0);
+
+        // Testing different ranks and with different order of the parameters
+        assertTrue(comparator.compare(rank1_1, rank2) < 0);
+        assertTrue(comparator.compare(rank2, rank1_1) > 0);
+    }
+
+    public void testUnknownRank() {
+        DummyObject knownRank = new DummyObject(RANK1);
+        DummyObject unknownRank1 = new DummyObject(UNKNOWN_RANK1);
+        DummyObject unknownRank2 = new DummyObject(UNKNOWN_RANK2);
+
+        assertTrue("Known rank should be smaller than unknown rank.",
+                comparator.compare(knownRank, unknownRank1) < 0);
+        assertTrue("Unknown rank should be larger than known rank.",
+                comparator.compare(unknownRank1, knownRank) > 0);
+        assertTrue("Two different unknown ranks should be equal.",
+                comparator.compare(unknownRank1, unknownRank2) == 0);
+    }
+
+    public void testNullRank() {
+        DummyObject knownRank = new DummyObject(RANK1);
+        DummyObject unknownRank = new DummyObject(UNKNOWN_RANK1);
+        DummyObject nullRank = new DummyObject(NULL_RANK);
+
+        assertTrue("Known rank should be smaller than null rank.",
+                comparator.compare(knownRank, nullRank) < 0);
+        assertTrue("null rank should be larger than known rank.",
+                comparator.compare(nullRank, knownRank) > 0);
+        assertTrue("Unknown and null rank should be equal.",
+                comparator.compare(unknownRank, nullRank) == 0);
+    }
+
+    private static final Function<DummyObject, String> DUMMY_OBJECT_TO_RANK_FUNCTION =
+            new Function<DummyObject, String>() {
+                @Override
+                public String apply(DummyObject dummyObject) {
+                    return dummyObject.rank;
+                }
+            };
+
+    private class DummyObject {
+        private final String rank;
+
+        private DummyObject(String rank) {
+            this.rank = rank;
+        }
+    }
+}