ChromeFeatureList meta tests demonstrating its behavior in unit tests.

Bug: 1053463
Change-Id: I3fd46315c971c6377e194f956b769950b9129d1d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2064183Reviewed-by: David Trainor <dtrainor@chromium.org>
Commit-Queue: Henrique Nakashima <hnakashima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#743325}

chrome/android/BUILD.gn

@@ -664,6 +664,7 @@ junit_binary("chrome_junit_tests") {
     "//chrome/android/webapk/libs/client:client_java",
     "//chrome/android/webapk/libs/common:common_java",
     "//chrome/android/webapk/test:junit_test_support",
+    "//chrome/browser/flags:flags_junit_tests",
     "//chrome/browser/image_fetcher:java",
     "//chrome/browser/preferences:preferences_junit_tests",
     "//chrome/browser/thumbnail:java",

chrome/browser/flags/BUILD.gn

@@ -24,3 +24,21 @@ generate_jni("jni_headers") {
     "android/java/src/org/chromium/chrome/browser/flags/ChromeFeatureList.java",
   ]
 }
+
+java_library("flags_junit_tests") {
+  # Skip platform checks since Robolectric depends on requires_android targets.
+  bypass_platform_checks = true
+  testonly = true
+  sources = [
+    "android/java/src/org/chromium/chrome/browser/flags/ChromeFeatureListWithProcessorUnitTest.java",
+    "android/java/src/org/chromium/chrome/browser/flags/ChromeFeatureListWithoutProcessorUnitTest.java",
+  ]
+  deps = [
+    ":java",
+    "//base:base_java",
+    "//base:base_java_test_support",
+    "//base:base_junit_test_support",
+    "//base/test:test_support_java",
+    "//chrome/test/android:chrome_java_test_support",
+  ]
+}

chrome/browser/flags/android/chrome_feature_list.cc

@@ -199,6 +199,8 @@ const base::Feature* kFeaturesExposedToJava[] = {
     &kTabReparenting,
     &kTabSwitcherOnReturn,
     &kTabToGTSAnimation,
+    &kTestDefaultDisabled,
+    &kTestDefaultEnabled,
     &kTrustedWebActivityPostMessage,
     &kStartSurfaceAndroid,
     &kUmaBackgroundSessions,
@@ -591,6 +593,12 @@ const base::Feature kTabSwitcherOnReturn{"TabSwitcherOnReturn",
 const base::Feature kTabToGTSAnimation{"TabToGTSAnimation",
                                        base::FEATURE_DISABLED_BY_DEFAULT};
 
+const base::Feature kTestDefaultDisabled{"TestDefaultDisabled",
+                                         base::FEATURE_DISABLED_BY_DEFAULT};
+
+const base::Feature kTestDefaultEnabled{"TestDefaultEnabled",
+                                        base::FEATURE_ENABLED_BY_DEFAULT};
+
 const base::Feature kTrustedWebActivityPostMessage{
     "TrustedWebActivityPostMessage", base::FEATURE_DISABLED_BY_DEFAULT};
 

chrome/browser/flags/android/chrome_feature_list.h

@@ -122,6 +122,8 @@ extern const base::Feature kTabGridLayoutAndroid;
 extern const base::Feature kTabReparenting;
 extern const base::Feature kTabSwitcherOnReturn;
 extern const base::Feature kTabToGTSAnimation;
+extern const base::Feature kTestDefaultDisabled;
+extern const base::Feature kTestDefaultEnabled;
 extern const base::Feature kTrustedWebActivityPostMessage;
 extern const base::Feature kStartSurfaceAndroid;
 extern const base::Feature kUmaBackgroundSessions;

chrome/browser/flags/android/java/src/org/chromium/chrome/browser/flags/ChromeFeatureList.java

@@ -358,6 +358,8 @@ public abstract class ChromeFeatureList {
     public static final String TAB_REPARENTING = "TabReparenting";
     public static final String TAB_SWITCHER_ON_RETURN = "TabSwitcherOnReturn";
     public static final String TAB_TO_GTS_ANIMATION = "TabToGTSAnimation";
+    public static final String TEST_DEFAULT_DISABLED = "TestDefaultDisabled";
+    public static final String TEST_DEFAULT_ENABLED = "TestDefaultEnabled";
     public static final String TOUCH_TO_FILL_ANDROID = "TouchToFillAndroid";
     public static final String TRUSTED_WEB_ACTIVITY = "TrustedWebActivity";
     public static final String TRUSTED_WEB_ACTIVITY_POST_MESSAGE = "TrustedWebActivityPostMessage";

chrome/browser/flags/android/java/src/org/chromium/chrome/browser/flags/ChromeFeatureListWithProcessorUnitTest.java

+// Copyright 2020 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.chrome.browser.flags;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TestRule;
+import org.junit.runner.RunWith;
+import org.robolectric.annotation.Config;
+
+import org.chromium.base.test.BaseRobolectricTestRunner;
+import org.chromium.chrome.test.util.browser.Features;
+import org.chromium.chrome.test.util.browser.Features.DisableFeatures;
+import org.chromium.chrome.test.util.browser.Features.EnableFeatures;
+
+import java.util.Collections;
+
+/**
+ * Shows the behavior of {@link ChromeFeatureList} in Robolectric unit tests when the rule
+ * Features.JUnitProcessor is present.
+ */
+@RunWith(BaseRobolectricTestRunner.class)
+@Config(manifest = Config.NONE)
+public class ChromeFeatureListWithProcessorUnitTest {
+    @Rule
+    public TestRule mProcessor = new Features.JUnitProcessor();
+
+    /**
+     * In unit tests, all flags checked must have their value specified.
+     */
+    @Test(expected = IllegalArgumentException.class)
+    public void testNoOverridesDefaultDisabled_throws() {
+        ChromeFeatureList.isEnabled(ChromeFeatureList.TEST_DEFAULT_DISABLED);
+    }
+
+    /**
+     * In unit tests, all flags checked must have their value specified.
+     */
+    @Test(expected = IllegalArgumentException.class)
+    public void testNoOverridesDefaultEnabled_throws() {
+        ChromeFeatureList.isEnabled(ChromeFeatureList.TEST_DEFAULT_ENABLED);
+    }
+
+    /**
+     * In unit tests, flags may have their value specified by the EnableFeatures annotation.
+     */
+    @Test
+    @EnableFeatures(ChromeFeatureList.TEST_DEFAULT_DISABLED)
+    public void testAnnotationEnabled_returnsEnabled() {
+        assertTrue(ChromeFeatureList.isEnabled(ChromeFeatureList.TEST_DEFAULT_DISABLED));
+    }
+
+    /**
+     * In unit tests, flags may have their value specified by the DisableFeatures annotation.
+     */
+    @Test
+    @DisableFeatures(ChromeFeatureList.TEST_DEFAULT_DISABLED)
+    public void testAnnotationDisabled_returnsDisabled() {
+        assertFalse(ChromeFeatureList.isEnabled(ChromeFeatureList.TEST_DEFAULT_DISABLED));
+    }
+
+    /**
+     * In unit tests, flags may have their value specified by calling
+     * {@link ChromeFeatureList#setTestFeatures(java.util.Map)}.
+     */
+    @Test
+    public void testSetTestFeaturesEnabled_returnsEnabled() {
+        ChromeFeatureList.setTestFeatures(
+                Collections.singletonMap(ChromeFeatureList.TEST_DEFAULT_DISABLED, true));
+        assertTrue(ChromeFeatureList.isEnabled(ChromeFeatureList.TEST_DEFAULT_DISABLED));
+        ChromeFeatureList.setTestFeatures(null);
+    }
+
+    /**
+     * In unit tests, flags may have their value specified by calling
+     * {@link ChromeFeatureList#setTestFeatures(java.util.Map)}.
+     */
+    @Test
+    public void testSetTestFeaturesDisabled_returnsDisabled() {
+        ChromeFeatureList.setTestFeatures(
+                Collections.singletonMap(ChromeFeatureList.TEST_DEFAULT_DISABLED, false));
+        assertFalse(ChromeFeatureList.isEnabled(ChromeFeatureList.TEST_DEFAULT_DISABLED));
+        ChromeFeatureList.setTestFeatures(null);
+    }
+}

chrome/browser/flags/android/java/src/org/chromium/chrome/browser/flags/ChromeFeatureListWithoutProcessorUnitTest.java

+// Copyright 2020 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.chrome.browser.flags;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.annotation.Config;
+
+import org.chromium.base.test.BaseRobolectricTestRunner;
+import org.chromium.chrome.test.util.browser.Features.DisableFeatures;
+import org.chromium.chrome.test.util.browser.Features.EnableFeatures;
+
+import java.util.Collections;
+
+/**
+ * Shows the behavior of {@link ChromeFeatureList} in Robolectric unit tests when the rule
+ * Features.JUnitProcessor is NOT present.
+ */
+@RunWith(BaseRobolectricTestRunner.class)
+@Config(manifest = Config.NONE)
+public class ChromeFeatureListWithoutProcessorUnitTest {
+    /**
+     * In unit tests, all flags checked must have their value specified.
+     */
+    @Test(expected = AssertionError.class)
+    public void testNoOverridesDefaultDisabled_asserts() {
+        ChromeFeatureList.isEnabled(ChromeFeatureList.TEST_DEFAULT_DISABLED);
+    }
+
+    /**
+     * In unit tests, all flags checked must have their value specified.
+     */
+    @Test(expected = AssertionError.class)
+    public void testNoOverridesDefaultEnabled_asserts() {
+        ChromeFeatureList.isEnabled(ChromeFeatureList.TEST_DEFAULT_ENABLED);
+    }
+
+    /**
+     * In unit tests without a Features.JUnitProcessor, the EnableFeatures annotation does not
+     * work.
+     */
+    @Test(expected = AssertionError.class)
+    @EnableFeatures(ChromeFeatureList.TEST_DEFAULT_DISABLED)
+    public void testAnnotationEnabled_asserts() {
+        ChromeFeatureList.isEnabled(ChromeFeatureList.TEST_DEFAULT_DISABLED);
+    }
+
+    /**
+     * In unit tests without a Features.JUnitProcessor, the DisableFeatures annotation does not
+     * work.
+     */
+    @Test(expected = AssertionError.class)
+    @DisableFeatures(ChromeFeatureList.TEST_DEFAULT_DISABLED)
+    public void testAnnotationDisabled_asserts() {
+        ChromeFeatureList.isEnabled(ChromeFeatureList.TEST_DEFAULT_DISABLED);
+    }
+
+    /**
+     * In unit tests without a Features.JUnitProcessor, flags may have their value specified by
+     * calling {@link ChromeFeatureList#setTestFeatures(java.util.Map)}.
+     */
+    @Test
+    public void testSetTestFeaturesEnabled_returnsEnabled() {
+        ChromeFeatureList.setTestFeatures(
+                Collections.singletonMap(ChromeFeatureList.TEST_DEFAULT_DISABLED, true));
+        assertTrue(ChromeFeatureList.isEnabled(ChromeFeatureList.TEST_DEFAULT_DISABLED));
+        ChromeFeatureList.setTestFeatures(null);
+    }
+
+    /**
+     * In unit tests without a Features.JUnitProcessor, flags may have their value specified by
+     * calling {@link ChromeFeatureList#setTestFeatures(java.util.Map)}.
+     */
+    @Test
+    public void testSetTestFeaturesDisabled_returnsDisabled() {
+        ChromeFeatureList.setTestFeatures(
+                Collections.singletonMap(ChromeFeatureList.TEST_DEFAULT_DISABLED, false));
+        assertFalse(ChromeFeatureList.isEnabled(ChromeFeatureList.TEST_DEFAULT_DISABLED));
+        ChromeFeatureList.setTestFeatures(null);
+    }
+}