Create CommandLineTestRule

base/test/android/junit/src/org/chromium/base/test/CommandLineFlagsTest.java

Index: base/test/android/junit/src/org/chromium/base/test/CommandLineFlagsTest.java
diff --git a/base/test/android/junit/src/org/chromium/base/test/CommandLineFlagsTest.java b/base/test/android/junit/src/org/chromium/base/test/CommandLineFlagsTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..c3b159bc10e344f8e08e8522ea0937a0bf4ee0aa
--- /dev/null
+++ b/base/test/android/junit/src/org/chromium/base/test/CommandLineFlagsTest.java
@@ -0,0 +1,142 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.base.test;
+
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.Description;
+import org.junit.runner.RunWith;
+import org.junit.runners.BlockJUnit4ClassRunner;
+
+import org.chromium.base.CommandLine;
+import org.chromium.base.test.util.CommandLineFlags;
+
+import java.lang.annotation.Annotation;
+import java.lang.reflect.Method;
+import java.util.Arrays;
+import java.util.Set;
+
+/** Unit tests for CommandLineFlags. */
+@RunWith(BlockJUnit4ClassRunner.class)
+public class CommandLineFlagsTest {
+    @CommandLineFlags.Add("A")
+    class ParentClassAddFlagA {
+        @CommandLineFlags.Remove("A")
+        public void testMethodRemoveFlagA() {}
+
+        @CommandLineFlags.Add("B")
+        public void testMethodAddFlagB() {}
+    }
+
+    @CommandLineFlags.Remove("A")
+    class ChildClassRemoveFlagA extends ParentClassAddFlagA {
+        public void testMethod() {}
+
+        @CommandLineFlags.Add("A")
+        public void testMethodAddFlagA() {}
+    }
+

[jbudorick, 2016/11/23 16:07:36]

One more test case: a second class that extends ParentClassAddFlagA and doesn't
remove A.

[the real yoland, 2016/11/23 20:44:36]

Done

+    class EmptyClass {
+        public void testEmpty() {}
+    }
+
+    @Before
+    public void setUp() {
+        CommandLine.init(new String[0]);
+    }
+
+    @Test
+    public void testGetFlagsParentRemoveA() throws Throwable {
+        Method method = ParentClassAddFlagA.class.getDeclaredMethod("testMethodRemoveFlagA");
+        Set<String> flags = CommandLineFlags.getFlags(method);
+        Assert.assertEquals("testMethodRemoveFlagA should have no flag", 0, flags.size());
+    }
+
+    @Test
+    public void testGetFlagsParentRemoveAWithDesc() throws Throwable {
+        Annotation[] annotations = ParentClassAddFlagA.class.getMethod("testMethodRemoveFlagA")
+                                           .getDeclaredAnnotations();
+        Description desc = Description.createTestDescription(
+                ParentClassAddFlagA.class, "testMethodRemoveFlagA", annotations);
+        Set<String> flags = CommandLineFlags.getFlags(desc);
+        Assert.assertEquals(String.format("testMethodRemoveFlagA should have no flag %s",
+                                    Arrays.toString(flags.toArray())),
+                0, flags.size());
+    }
+
+    @Test
+    public void testGetFlagsParentAddB() throws Throwable {
+        Method method = ParentClassAddFlagA.class.getDeclaredMethod("testMethodAddFlagB");
+        Set<String> flags = CommandLineFlags.getFlags(method);
+        Assert.assertEquals("testMethodAddFlagB should have 2 flags", 2, flags.size());
+        Assert.assertTrue("testMethodAddFlagB should have both A and B flag", flags.contains("A"));
+        Assert.assertTrue("testMethodAddFlagB should have both A and B flag", flags.contains("B"));
+    }
+
+    @Test
+    public void testGetFlagsParentAddBWithDesc() throws Throwable {
+        Annotation[] annotations =
+                ParentClassAddFlagA.class.getMethod("testMethodAddFlagB").getDeclaredAnnotations();
+        Description desc = Description.createTestDescription(
+                ParentClassAddFlagA.class, "testMethodAddFlagB", annotations);
+        Set<String> flags = CommandLineFlags.getFlags(desc);
+        Assert.assertEquals("testMethodAddFlagB should have 2 flags", 2, flags.size());
+        Assert.assertTrue("testMethodAddFlagB should have both A and B flag", flags.contains("A"));
+        Assert.assertTrue("testMethodAddFlagB should have both A and B flag", flags.contains("B"));
+    }
+
+    @Test
+    public void testGetFlagsChild() throws Throwable {
+        Method method = ChildClassRemoveFlagA.class.getMethod("testMethod");
+        Set<String> flags = CommandLineFlags.getFlags(method);
+        Assert.assertEquals("testMethod should have no flag", 0, flags.size());
+    }
+
+    @Test
+    public void testGetFlagsChildWithDesc() throws Throwable {
+        Annotation[] annotations =
+                ChildClassRemoveFlagA.class.getMethod("testMethod").getDeclaredAnnotations();
+        Description desc = Description.createTestDescription(
+                ChildClassRemoveFlagA.class, "testMethod", annotations);
+        Set<String> flags = CommandLineFlags.getFlags(desc);
+        Assert.assertEquals("testMethodRemoveFlagA should have no flag", 0, flags.size());
+    }
+
+    @Test
+    public void testGetFlagsChildAddA() throws Throwable {
+        Method method = ChildClassRemoveFlagA.class.getMethod("testMethodAddFlagA");
+        Set<String> flags = CommandLineFlags.getFlags(method);
+        Assert.assertEquals("testMethodAddFlagB should have 1 flag", 1, flags.size());
+        Assert.assertTrue("testMethodAddFlagB should have A flag", flags.contains("A"));
+    }
+
+    @Test
+    public void testGetFlagsChildAddAWithDesc() throws Throwable {
+        Annotation[] annotations = ChildClassRemoveFlagA.class.getMethod("testMethodAddFlagA")
+                                           .getDeclaredAnnotations();
+        Description desc = Description.createTestDescription(
+                ChildClassRemoveFlagA.class, "testMethodAddFlagA", annotations);
+        Set<String> flags = CommandLineFlags.getFlags(desc);
+        Assert.assertEquals("testMethodAddFlagB should have 1 flag", 1, flags.size());
+        Assert.assertTrue("testMethodAddFlagB should have A flag", flags.contains("A"));
+    }
+
+    @Test
+    public void testEmptyClass() throws Throwable {
+        Method method = EmptyClass.class.getMethod("testEmpty");
+        Set<String> flags = CommandLineFlags.getFlags(method);
+        Assert.assertEquals("EmptyClass method should have 0 flag", 0, flags.size());
+    }
+
+    @Test
+    public void testEmptyClassWithDesc() throws Throwable {
+        Annotation[] annotations = EmptyClass.class.getMethod("testEmpty").getDeclaredAnnotations();
+        Description desc =
+                Description.createTestDescription(EmptyClass.class, "testEmpty", annotations);
+        Set<String> flags = CommandLineFlags.getFlags(desc);
+        Assert.assertEquals("EmptyClass method should have 0 flag", 0, flags.size());
+    }
+}