Add tests to ensure DefaultRenderersFactory reflection works

Also add explicit Lint.IfChange/ThenChange rules to make it
clearer what needs to be done when changing one of the code
paths that's accessed via reflection.

PiperOrigin-RevId: 233406709

extensions/ffmpeg/build.gradle

@@ -38,6 +38,8 @@ dependencies {
     implementation project(modulePrefix + 'library-core')
     implementation 'com.android.support:support-annotations:' + supportLibraryVersion
     compileOnly 'org.checkerframework:checker-qual:' + checkerframeworkVersion
+    testImplementation project(modulePrefix + 'testutils-robolectric')
+    testImplementation 'junit:junit:' + junitVersion
 }
 
 ext {

extensions/ffmpeg/src/test/AndroidManifest.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2019 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.
+-->
+
+<manifest package="com.google.android.exoplayer2.ext.ffmpeg"/>

extensions/ffmpeg/src/test/java/com/google/android/exoplayer2/ext/ffmpeg/DefaultRenderersFactoryTest.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2019 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.google.android.exoplayer2.ext.ffmpeg;
+
+import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.testutil.DefaultRenderersFactoryAsserts;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+
+/** Unit test for {@link DefaultRenderersFactoryTest} with {@link FfmpegAudioRenderer}. */
+@RunWith(RobolectricTestRunner.class)
+public final class DefaultRenderersFactoryTest {
+
+  @Test
+  public void createRenderers_instantiatesVpxRenderer() {
+    DefaultRenderersFactoryAsserts.assertExtensionRendererCreated(
+        FfmpegAudioRenderer.class, C.TRACK_TYPE_AUDIO);
+  }
+}

extensions/ffmpeg/src/test/resources/robolectric.properties

@@ -0,0 +1 @@
+manifest=src/test/AndroidManifest.xml

extensions/flac/build.gradle

@@ -36,11 +36,12 @@ android {
 }
 
 dependencies {
-    implementation 'com.android.support:support-annotations:' + supportLibraryVersion
     implementation project(modulePrefix + 'library-core')
-    androidTestImplementation 'androidx.test:runner:' + testRunnerVersion
+    implementation 'com.android.support:support-annotations:' + supportLibraryVersion
     androidTestImplementation project(modulePrefix + 'testutils')
+    androidTestImplementation 'androidx.test:runner:' + testRunnerVersion
     testImplementation project(modulePrefix + 'testutils-robolectric')
+    testImplementation 'org.robolectric:robolectric:' + robolectricVersion
 }
 
 ext {

extensions/flac/src/main/java/com/google/android/exoplayer2/ext/flac/FlacExtractor.java

@@ -94,7 +94,7 @@ public final class FlacExtractor implements Extractor {
 
   /** Constructs an instance with flags = 0. */
   public FlacExtractor() {
-    this(0);
+    this(/* flags= */ 0);
   }
 
   /**

extensions/flac/src/main/java/com/google/android/exoplayer2/ext/flac/LibflacAudioRenderer.java

@@ -42,7 +42,9 @@ public class LibflacAudioRenderer extends SimpleDecoderAudioRenderer {
    * @param eventListener A listener of events. May be null if delivery of events is not required.
    * @param audioProcessors Optional {@link AudioProcessor}s that will process audio before output.
    */
-  public LibflacAudioRenderer(Handler eventHandler, AudioRendererEventListener eventListener,
+  public LibflacAudioRenderer(
+      Handler eventHandler,
+      AudioRendererEventListener eventListener,
       AudioProcessor... audioProcessors) {
     super(eventHandler, eventListener, audioProcessors);
   }

extensions/flac/src/test/java/com/google/android/exoplayer2/ext/flac/DefaultRenderersFactoryTest.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2019 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.google.android.exoplayer2.ext.flac;
+
+import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.testutil.DefaultRenderersFactoryAsserts;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+
+/** Unit test for {@link DefaultRenderersFactoryTest} with {@link LibflacAudioRenderer}. */
+@RunWith(RobolectricTestRunner.class)
+public final class DefaultRenderersFactoryTest {
+
+  @Test
+  public void createRenderers_instantiatesVpxRenderer() {
+    DefaultRenderersFactoryAsserts.assertExtensionRendererCreated(
+        LibflacAudioRenderer.class, C.TRACK_TYPE_AUDIO);
+  }
+}

extensions/opus/build.gradle

@@ -37,6 +37,8 @@ android {
 
 dependencies {
     implementation project(modulePrefix + 'library-core')
+    testImplementation project(modulePrefix + 'testutils-robolectric')
+    testImplementation 'junit:junit:' + junitVersion
     androidTestImplementation 'androidx.test:runner:' + testRunnerVersion
 }
 

extensions/opus/src/main/java/com/google/android/exoplayer2/ext/opus/LibopusAudioRenderer.java

@@ -47,7 +47,9 @@ public final class LibopusAudioRenderer extends SimpleDecoderAudioRenderer {
    * @param eventListener A listener of events. May be null if delivery of events is not required.
    * @param audioProcessors Optional {@link AudioProcessor}s that will process audio before output.
    */
-  public LibopusAudioRenderer(Handler eventHandler, AudioRendererEventListener eventListener,
+  public LibopusAudioRenderer(
+      Handler eventHandler,
+      AudioRendererEventListener eventListener,
       AudioProcessor... audioProcessors) {
     super(eventHandler, eventListener, audioProcessors);
   }

extensions/opus/src/test/AndroidManifest.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2019 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.
+-->
+
+<manifest package="com.google.android.exoplayer2.ext.opus"/>

extensions/opus/src/test/java/com/google/android/exoplayer2/ext/opus/DefaultRenderersFactoryTest.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2019 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.google.android.exoplayer2.ext.opus;
+
+import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.testutil.DefaultRenderersFactoryAsserts;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+
+/** Unit test for {@link DefaultRenderersFactoryTest} with {@link LibopusAudioRenderer}. */
+@RunWith(RobolectricTestRunner.class)
+public final class DefaultRenderersFactoryTest {
+
+  @Test
+  public void createRenderers_instantiatesVpxRenderer() {
+    DefaultRenderersFactoryAsserts.assertExtensionRendererCreated(
+        LibopusAudioRenderer.class, C.TRACK_TYPE_AUDIO);
+  }
+}

extensions/opus/src/test/resources/robolectric.properties

@@ -0,0 +1 @@
+manifest=src/test/AndroidManifest.xml

extensions/vp9/build.gradle

@@ -38,6 +38,8 @@ android {
 dependencies {
     implementation project(modulePrefix + 'library-core')
     implementation 'com.android.support:support-annotations:' + supportLibraryVersion
+    testImplementation project(modulePrefix + 'testutils-robolectric')
+    testImplementation 'junit:junit:' + junitVersion
     androidTestImplementation 'androidx.test:runner:' + testRunnerVersion
     androidTestImplementation 'com.google.truth:truth:' + truthVersion
 }

extensions/vp9/src/test/AndroidManifest.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2019 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.
+-->
+
+<manifest package="com.google.android.exoplayer2.ext.vp9"/>

extensions/vp9/src/test/java/com/google/android/exoplayer2/ext/vp9/DefaultRenderersFactoryTest.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2019 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.google.android.exoplayer2.ext.vp9;
+
+import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.testutil.DefaultRenderersFactoryAsserts;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+
+/** Unit test for {@link DefaultRenderersFactoryTest} with {@link LibvpxVideoRenderer}. */
+@RunWith(RobolectricTestRunner.class)
+public final class DefaultRenderersFactoryTest {
+
+  @Test
+  public void createRenderers_instantiatesVpxRenderer() {
+    DefaultRenderersFactoryAsserts.assertExtensionRendererCreated(
+        LibvpxVideoRenderer.class, C.TRACK_TYPE_VIDEO);
+  }
+}

extensions/vp9/src/test/resources/robolectric.properties

@@ -0,0 +1 @@
+manifest=src/test/AndroidManifest.xml

testutils_robolectric/src/main/java/com/google/android/exoplayer2/testutil/DefaultRenderersFactoryAsserts.java

@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2019 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.google.android.exoplayer2.testutil;
+
+import static com.google.android.exoplayer2.DefaultRenderersFactory.EXTENSION_RENDERER_MODE_OFF;
+import static com.google.android.exoplayer2.DefaultRenderersFactory.EXTENSION_RENDERER_MODE_ON;
+import static com.google.android.exoplayer2.DefaultRenderersFactory.EXTENSION_RENDERER_MODE_PREFER;
+import static com.google.common.truth.Truth.assertThat;
+
+import android.os.Handler;
+import android.os.Looper;
+import com.google.android.exoplayer2.DefaultRenderersFactory;
+import com.google.android.exoplayer2.Renderer;
+import com.google.android.exoplayer2.audio.AudioRendererEventListener;
+import com.google.android.exoplayer2.metadata.Metadata;
+import com.google.android.exoplayer2.text.Cue;
+import com.google.android.exoplayer2.video.VideoRendererEventListener;
+import java.util.List;
+import org.robolectric.RuntimeEnvironment;
+
+/** Assertions for {@link DefaultRenderersFactory}. */
+public final class DefaultRenderersFactoryAsserts {
+
+  /**
+   * Asserts that an extension renderer of type {@code clazz} is not instantiated for {@link
+   * DefaultRenderersFactory#EXTENSION_RENDERER_MODE_OFF}, and that it's instantiated in the correct
+   * position relative to other renderers of the same type for {@link
+   * DefaultRenderersFactory#EXTENSION_RENDERER_MODE_ON} and {@link
+   * DefaultRenderersFactory#EXTENSION_RENDERER_MODE_PREFER}, assuming no other extension renderers
+   * can be loaded.
+   *
+   * @param clazz The extension renderer class.
+   * @param type The type of the renderer.
+   */
+  public static void assertExtensionRendererCreated(Class<? extends Renderer> clazz, int type) {
+    // In EXTENSION_RENDERER_MODE_OFF the renderer should not be created.
+    Renderer[] renderers = createRenderers(EXTENSION_RENDERER_MODE_OFF);
+    for (Renderer renderer : renderers) {
+      assertThat(renderer).isNotInstanceOf(clazz);
+    }
+
+    // In EXTENSION_RENDERER_MODE_ON the renderer should be created and last of its type.
+    renderers = createRenderers(EXTENSION_RENDERER_MODE_ON);
+    boolean found = false;
+    for (Renderer renderer : renderers) {
+      if (!found) {
+        if (clazz.isInstance(renderer)) {
+          found = true;
+        }
+      } else {
+        assertThat(renderer.getTrackType()).isNotEqualTo(type);
+      }
+    }
+    assertThat(found).isTrue();
+
+    // In EXTENSION_RENDERER_MODE_PREFER the renderer should be created and first of its type.
+    renderers = createRenderers(EXTENSION_RENDERER_MODE_PREFER);
+    found = false;
+    for (Renderer renderer : renderers) {
+      if (!found) {
+        if (clazz.isInstance(renderer)) {
+          found = true;
+        } else {
+          assertThat(renderer.getTrackType()).isNotEqualTo(type);
+        }
+      } else {
+        assertThat(renderer).isNotInstanceOf(clazz);
+      }
+    }
+    assertThat(found).isTrue();
+  }
+
+  private static Renderer[] createRenderers(
+      @DefaultRenderersFactory.ExtensionRendererMode int extensionRendererMode) {
+    DefaultRenderersFactory factory =
+        new DefaultRenderersFactory(RuntimeEnvironment.application)
+            .setExtensionRendererMode(extensionRendererMode);
+    return factory.createRenderers(
+        new Handler(Looper.getMainLooper()),
+        new VideoRendererEventListener() {},
+        new AudioRendererEventListener() {},
+        (List<Cue> cues) -> {},
+        (Metadata metadata) -> {},
+        /* drmSessionManager= */ null);
+  }
+}