diff --git a/extensions/flac/src/test/AndroidManifest.xml b/extensions/flac/src/test/AndroidManifest.xml
new file mode 100644
index 0000000000..1d68b376ac
--- /dev/null
+++ b/extensions/flac/src/test/AndroidManifest.xml
@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2016 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.flac"/>
diff --git a/extensions/flac/src/test/java/com/google/android/exoplayer2/ext/flac/DefaultExtractorsFactoryTest.java b/extensions/flac/src/test/java/com/google/android/exoplayer2/ext/flac/DefaultExtractorsFactoryTest.java
new file mode 100644
index 0000000000..e08f4dc28c
--- /dev/null
+++ b/extensions/flac/src/test/java/com/google/android/exoplayer2/ext/flac/DefaultExtractorsFactoryTest.java
@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2016 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 static com.google.common.truth.Truth.assertThat;
+
+import com.google.android.exoplayer2.extractor.DefaultExtractorsFactory;
+import com.google.android.exoplayer2.extractor.Extractor;
+import com.google.android.exoplayer2.extractor.amr.AmrExtractor;
+import com.google.android.exoplayer2.extractor.flv.FlvExtractor;
+import com.google.android.exoplayer2.extractor.mkv.MatroskaExtractor;
+import com.google.android.exoplayer2.extractor.mp3.Mp3Extractor;
+import com.google.android.exoplayer2.extractor.mp4.FragmentedMp4Extractor;
+import com.google.android.exoplayer2.extractor.mp4.Mp4Extractor;
+import com.google.android.exoplayer2.extractor.ogg.OggExtractor;
+import com.google.android.exoplayer2.extractor.ts.Ac3Extractor;
+import com.google.android.exoplayer2.extractor.ts.AdtsExtractor;
+import com.google.android.exoplayer2.extractor.ts.PsExtractor;
+import com.google.android.exoplayer2.extractor.ts.TsExtractor;
+import com.google.android.exoplayer2.extractor.wav.WavExtractor;
+import java.util.ArrayList;
+import java.util.List;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+
+/** Unit test for {@link DefaultExtractorsFactory}. */
+@RunWith(RobolectricTestRunner.class)
+public final class DefaultExtractorsFactoryTest {
+
+  @Test
+  public void testCreateExtractors_returnExpectedClasses() {
+    DefaultExtractorsFactory defaultExtractorsFactory = new DefaultExtractorsFactory();
+
+    Extractor[] extractors = defaultExtractorsFactory.createExtractors();
+    List<Class> listCreatedExtractorClasses = new ArrayList<>();
+    for (Extractor extractor : extractors) {
+      listCreatedExtractorClasses.add(extractor.getClass());
+    }
+
+    Class[] expectedExtractorClassses =
+        new Class[] {
+          MatroskaExtractor.class,
+          FragmentedMp4Extractor.class,
+          Mp4Extractor.class,
+          Mp3Extractor.class,
+          AdtsExtractor.class,
+          Ac3Extractor.class,
+          TsExtractor.class,
+          FlvExtractor.class,
+          OggExtractor.class,
+          PsExtractor.class,
+          WavExtractor.class,
+          AmrExtractor.class,
+          FlacExtractor.class
+        };
+
+    assertThat(listCreatedExtractorClasses).containsNoDuplicates();
+    assertThat(listCreatedExtractorClasses).containsExactlyElementsIn(expectedExtractorClassses);
+  }
+}
diff --git a/extensions/flac/src/test/resources/robolectric.properties b/extensions/flac/src/test/resources/robolectric.properties
new file mode 100644
index 0000000000..2f3210368e
--- /dev/null
+++ b/extensions/flac/src/test/resources/robolectric.properties
@@ -0,0 +1 @@
+manifest=src/test/AndroidManifest.xml
diff --git a/extensions/ima/src/test/AndroidManifest.xml b/extensions/ima/src/test/AndroidManifest.xml
new file mode 100644
index 0000000000..9a4e33189e
--- /dev/null
+++ b/extensions/ima/src/test/AndroidManifest.xml
@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2018 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.ima.test" />
diff --git a/extensions/ima/src/test/java/com/google/android/exoplayer2/ext/ima/FakeAd.java b/extensions/ima/src/test/java/com/google/android/exoplayer2/ext/ima/FakeAd.java
new file mode 100644
index 0000000000..284471adfc
--- /dev/null
+++ b/extensions/ima/src/test/java/com/google/android/exoplayer2/ext/ima/FakeAd.java
@@ -0,0 +1,189 @@
+/*
+ * Copyright (C) 2018 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.ima;
+
+import com.google.ads.interactivemedia.v3.api.Ad;
+import com.google.ads.interactivemedia.v3.api.AdPodInfo;
+import com.google.ads.interactivemedia.v3.api.UiElement;
+import java.util.Set;
+
+/** A fake ad for testing. */
+/* package */ final class FakeAd implements Ad {
+
+  private final boolean skippable;
+  private final AdPodInfo adPodInfo;
+
+  public FakeAd(boolean skippable, int podIndex, int totalAds, int adPosition) {
+    this.skippable = skippable;
+    adPodInfo =
+        new AdPodInfo() {
+          @Override
+          public int getTotalAds() {
+            return totalAds;
+          }
+
+          @Override
+          public int getAdPosition() {
+            return adPosition;
+          }
+
+          @Override
+          public int getPodIndex() {
+            return podIndex;
+          }
+
+          @Override
+          public boolean isBumper() {
+            throw new UnsupportedOperationException();
+          }
+
+          @Override
+          public double getMaxDuration() {
+            throw new UnsupportedOperationException();
+          }
+
+          @Override
+          public double getTimeOffset() {
+            throw new UnsupportedOperationException();
+          }
+        };
+  }
+
+  @Override
+  public boolean isSkippable() {
+    return skippable;
+  }
+
+  @Override
+  public AdPodInfo getAdPodInfo() {
+    return adPodInfo;
+  }
+
+  @Override
+  public String getAdId() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public String getCreativeId() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public String getCreativeAdId() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public String getUniversalAdIdValue() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public String getUniversalAdIdRegistry() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public String getAdSystem() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public String[] getAdWrapperIds() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public String[] getAdWrapperSystems() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public String[] getAdWrapperCreativeIds() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public boolean isLinear() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public double getSkipTimeOffset() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public boolean isUiDisabled() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public String getDescription() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public String getTitle() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public String getContentType() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public String getAdvertiserName() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public String getSurveyUrl() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public String getDealId() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public int getWidth() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public int getHeight() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public String getTraffickingParameters() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public double getDuration() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public Set<UiElement> getUiElements() {
+    throw new UnsupportedOperationException();
+  }
+}
diff --git a/extensions/ima/src/test/java/com/google/android/exoplayer2/ext/ima/FakeAdsLoader.java b/extensions/ima/src/test/java/com/google/android/exoplayer2/ext/ima/FakeAdsLoader.java
new file mode 100644
index 0000000000..a8f3daae33
--- /dev/null
+++ b/extensions/ima/src/test/java/com/google/android/exoplayer2/ext/ima/FakeAdsLoader.java
@@ -0,0 +1,100 @@
+/*
+ * Copyright (C) 2018 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.ima;
+
+import com.google.ads.interactivemedia.v3.api.AdErrorEvent.AdErrorListener;
+import com.google.ads.interactivemedia.v3.api.AdsManager;
+import com.google.ads.interactivemedia.v3.api.AdsManagerLoadedEvent;
+import com.google.ads.interactivemedia.v3.api.AdsRequest;
+import com.google.ads.interactivemedia.v3.api.ImaSdkSettings;
+import com.google.ads.interactivemedia.v3.api.StreamManager;
+import com.google.ads.interactivemedia.v3.api.StreamRequest;
+import com.google.android.exoplayer2.util.Assertions;
+import java.util.ArrayList;
+
+/** Fake {@link com.google.ads.interactivemedia.v3.api.AdsLoader} implementation for tests. */
+public final class FakeAdsLoader implements com.google.ads.interactivemedia.v3.api.AdsLoader {
+
+  private final ImaSdkSettings imaSdkSettings;
+  private final AdsManager adsManager;
+  private final ArrayList<AdsLoadedListener> adsLoadedListeners;
+  private final ArrayList<AdErrorListener> adErrorListeners;
+
+  public FakeAdsLoader(ImaSdkSettings imaSdkSettings, AdsManager adsManager) {
+    this.imaSdkSettings = Assertions.checkNotNull(imaSdkSettings);
+    this.adsManager = Assertions.checkNotNull(adsManager);
+    adsLoadedListeners = new ArrayList<>();
+    adErrorListeners = new ArrayList<>();
+  }
+
+  @Override
+  public void contentComplete() {
+    // Do nothing.
+  }
+
+  @Override
+  public ImaSdkSettings getSettings() {
+    return imaSdkSettings;
+  }
+
+  @Override
+  public void requestAds(AdsRequest adsRequest) {
+    for (AdsLoadedListener listener : adsLoadedListeners) {
+      listener.onAdsManagerLoaded(
+          new AdsManagerLoadedEvent() {
+            @Override
+            public AdsManager getAdsManager() {
+              return adsManager;
+            }
+
+            @Override
+            public StreamManager getStreamManager() {
+              throw new UnsupportedOperationException();
+            }
+
+            @Override
+            public Object getUserRequestContext() {
+              return adsRequest.getUserRequestContext();
+            }
+          });
+    }
+  }
+
+  @Override
+  public String requestStream(StreamRequest streamRequest) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public void addAdsLoadedListener(AdsLoadedListener adsLoadedListener) {
+    adsLoadedListeners.add(adsLoadedListener);
+  }
+
+  @Override
+  public void removeAdsLoadedListener(AdsLoadedListener adsLoadedListener) {
+    adsLoadedListeners.remove(adsLoadedListener);
+  }
+
+  @Override
+  public void addAdErrorListener(AdErrorListener adErrorListener) {
+    adErrorListeners.add(adErrorListener);
+  }
+
+  @Override
+  public void removeAdErrorListener(AdErrorListener adErrorListener) {
+    adErrorListeners.remove(adErrorListener);
+  }
+}
diff --git a/extensions/ima/src/test/java/com/google/android/exoplayer2/ext/ima/FakeAdsRequest.java b/extensions/ima/src/test/java/com/google/android/exoplayer2/ext/ima/FakeAdsRequest.java
new file mode 100644
index 0000000000..7c2c8a6e0b
--- /dev/null
+++ b/extensions/ima/src/test/java/com/google/android/exoplayer2/ext/ima/FakeAdsRequest.java
@@ -0,0 +1,132 @@
+/*
+ * Copyright (C) 2018 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.ima;
+
+import com.google.ads.interactivemedia.v3.api.AdDisplayContainer;
+import com.google.ads.interactivemedia.v3.api.AdsRequest;
+import com.google.ads.interactivemedia.v3.api.player.ContentProgressProvider;
+import java.util.List;
+import java.util.Map;
+
+/** Fake {@link AdsRequest} implementation for tests. */
+public final class FakeAdsRequest implements AdsRequest {
+
+  private String adTagUrl;
+  private String adsResponse;
+  private Object userRequestContext;
+  private AdDisplayContainer adDisplayContainer;
+  private ContentProgressProvider contentProgressProvider;
+
+  @Override
+  public void setAdTagUrl(String adTagUrl) {
+    this.adTagUrl = adTagUrl;
+  }
+
+  @Override
+  public String getAdTagUrl() {
+    return adTagUrl;
+  }
+
+  @Override
+  public void setExtraParameter(String s, String s1) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public String getExtraParameter(String s) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public Map<String, String> getExtraParameters() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public void setUserRequestContext(Object userRequestContext) {
+    this.userRequestContext = userRequestContext;
+  }
+
+  @Override
+  public Object getUserRequestContext() {
+    return userRequestContext;
+  }
+
+  @Override
+  public AdDisplayContainer getAdDisplayContainer() {
+    return adDisplayContainer;
+  }
+
+  @Override
+  public void setAdDisplayContainer(AdDisplayContainer adDisplayContainer) {
+    this.adDisplayContainer = adDisplayContainer;
+  }
+
+  @Override
+  public ContentProgressProvider getContentProgressProvider() {
+    return contentProgressProvider;
+  }
+
+  @Override
+  public void setContentProgressProvider(ContentProgressProvider contentProgressProvider) {
+    this.contentProgressProvider = contentProgressProvider;
+  }
+
+  @Override
+  public String getAdsResponse() {
+    return adsResponse;
+  }
+
+  @Override
+  public void setAdsResponse(String adsResponse) {
+    this.adsResponse = adsResponse;
+  }
+
+  @Override
+  public void setAdWillAutoPlay(boolean b) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public void setAdWillPlayMuted(boolean b) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public void setContentDuration(float v) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public void setContentKeywords(List<String> list) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public void setContentTitle(String s) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public void setVastLoadTimeout(float v) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public void setLiveStreamPrefetchSeconds(float v) {
+    throw new UnsupportedOperationException();
+  }
+}
diff --git a/extensions/ima/src/test/java/com/google/android/exoplayer2/ext/ima/FakePlayer.java b/extensions/ima/src/test/java/com/google/android/exoplayer2/ext/ima/FakePlayer.java
new file mode 100644
index 0000000000..11ed214279
--- /dev/null
+++ b/extensions/ima/src/test/java/com/google/android/exoplayer2/ext/ima/FakePlayer.java
@@ -0,0 +1,196 @@
+/*
+ * Copyright (C) 2018 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.ima;
+
+import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.Player;
+import com.google.android.exoplayer2.Timeline;
+import com.google.android.exoplayer2.testutil.StubExoPlayer;
+import java.util.ArrayList;
+
+/** A fake player for testing content/ad playback. */
+/* package */ final class FakePlayer extends StubExoPlayer {
+
+  private final ArrayList<Player.EventListener> listeners;
+  private final Timeline.Window window;
+  private final Timeline.Period period;
+
+  private boolean prepared;
+  private Timeline timeline;
+  private int state;
+  private boolean playWhenReady;
+  private long position;
+  private long contentPosition;
+  private boolean isPlayingAd;
+  private int adGroupIndex;
+  private int adIndexInAdGroup;
+
+  public FakePlayer() {
+    listeners = new ArrayList<>();
+    window = new Timeline.Window();
+    period = new Timeline.Period();
+    state = Player.STATE_IDLE;
+    playWhenReady = true;
+    timeline = Timeline.EMPTY;
+  }
+
+  /** Sets the timeline on this fake player, which notifies listeners with the changed timeline. */
+  public void updateTimeline(Timeline timeline) {
+    for (Player.EventListener listener : listeners) {
+      listener.onTimelineChanged(
+          timeline,
+          null,
+          prepared ? TIMELINE_CHANGE_REASON_DYNAMIC : TIMELINE_CHANGE_REASON_PREPARED);
+    }
+    prepared = true;
+  }
+
+  /**
+   * Sets the state of this player as if it were playing content at the given {@code position}. If
+   * an ad is currently playing, this will trigger a position discontinuity.
+   */
+  public void setPlayingContentPosition(long position) {
+    boolean notify = isPlayingAd;
+    isPlayingAd = false;
+    adGroupIndex = C.INDEX_UNSET;
+    adIndexInAdGroup = C.INDEX_UNSET;
+    this.position = position;
+    contentPosition = position;
+    if (notify) {
+      for (Player.EventListener listener : listeners) {
+        listener.onPositionDiscontinuity(DISCONTINUITY_REASON_AD_INSERTION);
+      }
+    }
+  }
+
+  /**
+   * Sets the state of this player as if it were playing an ad with the given indices at the given
+   * {@code position}. If the player is playing a different ad or content, this will trigger a
+   * position discontinuity.
+   */
+  public void setPlayingAdPosition(
+      int adGroupIndex, int adIndexInAdGroup, long position, long contentPosition) {
+    boolean notify = !isPlayingAd || this.adIndexInAdGroup != adIndexInAdGroup;
+    isPlayingAd = true;
+    this.adGroupIndex = adGroupIndex;
+    this.adIndexInAdGroup = adIndexInAdGroup;
+    this.position = position;
+    this.contentPosition = contentPosition;
+    if (notify) {
+      for (Player.EventListener listener : listeners) {
+        listener.onPositionDiscontinuity(DISCONTINUITY_REASON_AD_INSERTION);
+      }
+    }
+  }
+
+  /** Sets the state of this player with the given {@code STATE} constant. */
+  public void setState(int state, boolean playWhenReady) {
+    boolean notify = this.state != state || this.playWhenReady != playWhenReady;
+    this.state = state;
+    this.playWhenReady = playWhenReady;
+    if (notify) {
+      for (Player.EventListener listener : listeners) {
+        listener.onPlayerStateChanged(playWhenReady, state);
+      }
+    }
+  }
+
+  // ExoPlayer methods. Other methods are unsupported.
+
+  @Override
+  public void addListener(Player.EventListener listener) {
+    listeners.add(listener);
+  }
+
+  @Override
+  public void removeListener(Player.EventListener listener) {
+    listeners.remove(listener);
+  }
+
+  @Override
+  public int getPlaybackState() {
+    return state;
+  }
+
+  @Override
+  public boolean getPlayWhenReady() {
+    return playWhenReady;
+  }
+
+  @Override
+  public Timeline getCurrentTimeline() {
+    return timeline;
+  }
+
+  @Override
+  public int getCurrentPeriodIndex() {
+    return 0;
+  }
+
+  @Override
+  public int getCurrentWindowIndex() {
+    return 0;
+  }
+
+  @Override
+  public int getNextWindowIndex() {
+    return C.INDEX_UNSET;
+  }
+
+  @Override
+  public int getPreviousWindowIndex() {
+    return C.INDEX_UNSET;
+  }
+
+  @Override
+  public long getDuration() {
+    if (timeline.isEmpty()) {
+      return C.INDEX_UNSET;
+    }
+    if (isPlayingAd()) {
+      long adDurationUs =
+          timeline.getPeriod(0, period).getAdDurationUs(adGroupIndex, adIndexInAdGroup);
+      return C.usToMs(adDurationUs);
+    } else {
+      return timeline.getWindow(getCurrentWindowIndex(), window).getDurationMs();
+    }
+  }
+
+  @Override
+  public long getCurrentPosition() {
+    return position;
+  }
+
+  @Override
+  public boolean isPlayingAd() {
+    return isPlayingAd;
+  }
+
+  @Override
+  public int getCurrentAdGroupIndex() {
+    return adGroupIndex;
+  }
+
+  @Override
+  public int getCurrentAdIndexInAdGroup() {
+    return adIndexInAdGroup;
+  }
+
+  @Override
+  public long getContentPosition() {
+    return contentPosition;
+  }
+}
diff --git a/extensions/ima/src/test/java/com/google/android/exoplayer2/ext/ima/ImaAdsLoaderTest.java b/extensions/ima/src/test/java/com/google/android/exoplayer2/ext/ima/ImaAdsLoaderTest.java
new file mode 100644
index 0000000000..b0fe731480
--- /dev/null
+++ b/extensions/ima/src/test/java/com/google/android/exoplayer2/ext/ima/ImaAdsLoaderTest.java
@@ -0,0 +1,272 @@
+/*
+ * Copyright (C) 2018 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.ima;
+
+import static com.google.common.truth.Truth.assertThat;
+import static org.mockito.Mockito.atLeastOnce;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import android.net.Uri;
+import android.support.annotation.Nullable;
+import android.view.ViewGroup;
+import android.widget.FrameLayout;
+import com.google.ads.interactivemedia.v3.api.Ad;
+import com.google.ads.interactivemedia.v3.api.AdDisplayContainer;
+import com.google.ads.interactivemedia.v3.api.AdEvent;
+import com.google.ads.interactivemedia.v3.api.AdEvent.AdEventType;
+import com.google.ads.interactivemedia.v3.api.AdsManager;
+import com.google.ads.interactivemedia.v3.api.AdsRenderingSettings;
+import com.google.ads.interactivemedia.v3.api.ImaSdkSettings;
+import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.ExoPlaybackException;
+import com.google.android.exoplayer2.Player;
+import com.google.android.exoplayer2.Timeline;
+import com.google.android.exoplayer2.source.SinglePeriodTimeline;
+import com.google.android.exoplayer2.source.ads.AdPlaybackState;
+import com.google.android.exoplayer2.source.ads.AdsLoader;
+import com.google.android.exoplayer2.source.ads.AdsMediaSource.AdLoadException;
+import com.google.android.exoplayer2.source.ads.SinglePeriodAdTimeline;
+import com.google.android.exoplayer2.upstream.DataSpec;
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Map;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.RuntimeEnvironment;
+
+/** Test for {@link ImaAdsLoader}. */
+@RunWith(RobolectricTestRunner.class)
+public class ImaAdsLoaderTest {
+
+  private static final long CONTENT_DURATION_US = 10 * C.MICROS_PER_SECOND;
+  private static final Timeline CONTENT_TIMELINE =
+      new SinglePeriodTimeline(CONTENT_DURATION_US, /* isSeekable= */ true, /* isDynamic= */ false);
+  private static final Uri TEST_URI = Uri.EMPTY;
+  private static final long TEST_AD_DURATION_US = 5 * C.MICROS_PER_SECOND;
+  private static final long[][] PREROLL_ADS_DURATIONS_US = new long[][] {{TEST_AD_DURATION_US}};
+  private static final Float[] PREROLL_CUE_POINTS_SECONDS = new Float[] {0f};
+  private static final FakeAd UNSKIPPABLE_AD =
+      new FakeAd(/* skippable= */ false, /* podIndex= */ 0, /* totalAds= */ 1, /* adPosition= */ 1);
+
+  private @Mock ImaSdkSettings imaSdkSettings;
+  private @Mock AdsRenderingSettings adsRenderingSettings;
+  private @Mock AdDisplayContainer adDisplayContainer;
+  private @Mock AdsManager adsManager;
+  private SingletonImaFactory testImaFactory;
+  private ViewGroup adUiViewGroup;
+  private TestAdsLoaderListener adsLoaderListener;
+  private FakePlayer fakeExoPlayer;
+  private ImaAdsLoader imaAdsLoader;
+
+  @Before
+  public void setUp() {
+    MockitoAnnotations.initMocks(this);
+    FakeAdsRequest fakeAdsRequest = new FakeAdsRequest();
+    FakeAdsLoader fakeAdsLoader = new FakeAdsLoader(imaSdkSettings, adsManager);
+    testImaFactory =
+        new SingletonImaFactory(
+            imaSdkSettings,
+            adsRenderingSettings,
+            adDisplayContainer,
+            fakeAdsRequest,
+            fakeAdsLoader);
+    adUiViewGroup = new FrameLayout(RuntimeEnvironment.application);
+  }
+
+  @After
+  public void teardown() {
+    if (imaAdsLoader != null) {
+      imaAdsLoader.release();
+    }
+  }
+
+  @Test
+  public void testBuilder_overridesPlayerType() {
+    when(imaSdkSettings.getPlayerType()).thenReturn("test player type");
+    setupPlayback(CONTENT_TIMELINE, PREROLL_ADS_DURATIONS_US, PREROLL_CUE_POINTS_SECONDS);
+
+    verify(imaSdkSettings).setPlayerType("google/exo.ext.ima");
+  }
+
+  @Test
+  public void testAttachPlayer_setsAdUiViewGroup() {
+    setupPlayback(CONTENT_TIMELINE, PREROLL_ADS_DURATIONS_US, PREROLL_CUE_POINTS_SECONDS);
+    imaAdsLoader.attachPlayer(fakeExoPlayer, adsLoaderListener, adUiViewGroup);
+
+    verify(adDisplayContainer, atLeastOnce()).setAdContainer(adUiViewGroup);
+  }
+
+  @Test
+  public void testAttachPlayer_updatesAdPlaybackState() {
+    setupPlayback(CONTENT_TIMELINE, PREROLL_ADS_DURATIONS_US, PREROLL_CUE_POINTS_SECONDS);
+    imaAdsLoader.attachPlayer(fakeExoPlayer, adsLoaderListener, adUiViewGroup);
+
+    assertThat(adsLoaderListener.adPlaybackState)
+        .isEqualTo(
+            new AdPlaybackState(/* adGroupTimesUs= */ 0)
+                .withAdDurationsUs(PREROLL_ADS_DURATIONS_US));
+  }
+
+  @Test
+  public void testAttachAfterRelease() {
+    setupPlayback(CONTENT_TIMELINE, PREROLL_ADS_DURATIONS_US, PREROLL_CUE_POINTS_SECONDS);
+    imaAdsLoader.release();
+    imaAdsLoader.attachPlayer(fakeExoPlayer, adsLoaderListener, adUiViewGroup);
+  }
+
+  @Test
+  public void testAttachAndCallbacksAfterRelease() {
+    setupPlayback(CONTENT_TIMELINE, PREROLL_ADS_DURATIONS_US, PREROLL_CUE_POINTS_SECONDS);
+    imaAdsLoader.release();
+    imaAdsLoader.attachPlayer(fakeExoPlayer, adsLoaderListener, adUiViewGroup);
+    fakeExoPlayer.setPlayingContentPosition(/* position= */ 0);
+    fakeExoPlayer.setState(Player.STATE_READY, true);
+
+    // If callbacks are invoked there is no crash.
+    // Note: we can't currently call getContentProgress/getAdProgress as a VerifyError is thrown
+    // when using Robolectric and accessing VideoProgressUpdate.VIDEO_TIME_NOT_READY, due to the IMA
+    // SDK being proguarded.
+    imaAdsLoader.requestAds(adUiViewGroup);
+    imaAdsLoader.onAdEvent(getAdEvent(AdEventType.LOADED, UNSKIPPABLE_AD));
+    imaAdsLoader.loadAd(TEST_URI.toString());
+    imaAdsLoader.onAdEvent(getAdEvent(AdEventType.CONTENT_PAUSE_REQUESTED, UNSKIPPABLE_AD));
+    imaAdsLoader.playAd();
+    imaAdsLoader.onAdEvent(getAdEvent(AdEventType.STARTED, UNSKIPPABLE_AD));
+    imaAdsLoader.pauseAd();
+    imaAdsLoader.stopAd();
+    imaAdsLoader.onPlayerError(ExoPlaybackException.createForSource(new IOException()));
+    imaAdsLoader.onPositionDiscontinuity(Player.DISCONTINUITY_REASON_SEEK);
+    imaAdsLoader.onAdEvent(getAdEvent(AdEventType.CONTENT_RESUME_REQUESTED, /* ad= */ null));
+    imaAdsLoader.handlePrepareError(
+        /* adGroupIndex= */ 0, /* adIndexInAdGroup= */ 0, new IOException());
+  }
+
+  @Test
+  public void testPlayback_withPrerollAd_marksAdAsPlayed() {
+    setupPlayback(CONTENT_TIMELINE, PREROLL_ADS_DURATIONS_US, PREROLL_CUE_POINTS_SECONDS);
+
+    // Load the preroll ad.
+    imaAdsLoader.attachPlayer(fakeExoPlayer, adsLoaderListener, adUiViewGroup);
+    imaAdsLoader.onAdEvent(getAdEvent(AdEventType.LOADED, UNSKIPPABLE_AD));
+    imaAdsLoader.loadAd(TEST_URI.toString());
+    imaAdsLoader.onAdEvent(getAdEvent(AdEventType.CONTENT_PAUSE_REQUESTED, UNSKIPPABLE_AD));
+
+    // Play the preroll ad.
+    imaAdsLoader.playAd();
+    fakeExoPlayer.setPlayingAdPosition(
+        /* adGroupIndex= */ 0,
+        /* adIndexInAdGroup= */ 0,
+        /* position= */ 0,
+        /* contentPosition= */ 0);
+    fakeExoPlayer.setState(Player.STATE_READY, true);
+    imaAdsLoader.onAdEvent(getAdEvent(AdEventType.STARTED, UNSKIPPABLE_AD));
+    imaAdsLoader.onAdEvent(getAdEvent(AdEventType.FIRST_QUARTILE, UNSKIPPABLE_AD));
+    imaAdsLoader.onAdEvent(getAdEvent(AdEventType.MIDPOINT, UNSKIPPABLE_AD));
+    imaAdsLoader.onAdEvent(getAdEvent(AdEventType.THIRD_QUARTILE, UNSKIPPABLE_AD));
+
+    // Play the content.
+    fakeExoPlayer.setPlayingContentPosition(0);
+    imaAdsLoader.stopAd();
+    imaAdsLoader.onAdEvent(getAdEvent(AdEventType.CONTENT_RESUME_REQUESTED, /* ad= */ null));
+
+    // Verify that the preroll ad has been marked as played.
+    assertThat(adsLoaderListener.adPlaybackState)
+        .isEqualTo(
+            new AdPlaybackState(/* adGroupTimesUs= */ 0)
+                .withContentDurationUs(CONTENT_DURATION_US)
+                .withAdCount(/* adGroupIndex= */ 0, /* adCount= */ 1)
+                .withAdUri(/* adGroupIndex= */ 0, /* adIndexInAdGroup= */ 0, /* uri= */ TEST_URI)
+                .withAdDurationsUs(PREROLL_ADS_DURATIONS_US)
+                .withPlayedAd(/* adGroupIndex= */ 0, /* adIndexInAdGroup= */ 0)
+                .withAdResumePositionUs(/* adResumePositionUs= */ 0));
+  }
+
+  private void setupPlayback(Timeline contentTimeline, long[][] adDurationsUs, Float[] cuePoints) {
+    fakeExoPlayer = new FakePlayer();
+    adsLoaderListener = new TestAdsLoaderListener(fakeExoPlayer, contentTimeline, adDurationsUs);
+    when(adsManager.getAdCuePoints()).thenReturn(Arrays.asList(cuePoints));
+    imaAdsLoader =
+        new ImaAdsLoader.Builder(RuntimeEnvironment.application)
+            .setImaFactory(testImaFactory)
+            .setImaSdkSettings(imaSdkSettings)
+            .buildForAdTag(TEST_URI);
+  }
+
+  private static AdEvent getAdEvent(AdEventType adEventType, @Nullable Ad ad) {
+    return new AdEvent() {
+      @Override
+      public AdEventType getType() {
+        return adEventType;
+      }
+
+      @Override
+      public @Nullable Ad getAd() {
+        return ad;
+      }
+
+      @Override
+      public Map<String, String> getAdData() {
+        return Collections.emptyMap();
+      }
+    };
+  }
+
+  /** Ad loader event listener that forwards ad playback state to a fake player. */
+  private static final class TestAdsLoaderListener implements AdsLoader.EventListener {
+
+    private final FakePlayer fakeExoPlayer;
+    private final Timeline contentTimeline;
+    private final long[][] adDurationsUs;
+
+    public AdPlaybackState adPlaybackState;
+
+    public TestAdsLoaderListener(
+        FakePlayer fakeExoPlayer, Timeline contentTimeline, long[][] adDurationsUs) {
+      this.fakeExoPlayer = fakeExoPlayer;
+      this.contentTimeline = contentTimeline;
+      this.adDurationsUs = adDurationsUs;
+    }
+
+    @Override
+    public void onAdPlaybackState(AdPlaybackState adPlaybackState) {
+      adPlaybackState = adPlaybackState.withAdDurationsUs(adDurationsUs);
+      this.adPlaybackState = adPlaybackState;
+      fakeExoPlayer.updateTimeline(new SinglePeriodAdTimeline(contentTimeline, adPlaybackState));
+    }
+
+    @Override
+    public void onAdLoadError(AdLoadException error, DataSpec dataSpec) {
+      assertThat(error.type).isNotEqualTo(AdLoadException.TYPE_UNEXPECTED);
+    }
+
+    @Override
+    public void onAdClicked() {
+      // Do nothing.
+    }
+
+    @Override
+    public void onAdTapped() {
+      // Do nothing.
+    }
+  }
+}
diff --git a/extensions/ima/src/test/java/com/google/android/exoplayer2/ext/ima/SingletonImaFactory.java b/extensions/ima/src/test/java/com/google/android/exoplayer2/ext/ima/SingletonImaFactory.java
new file mode 100644
index 0000000000..dd46d8a68b
--- /dev/null
+++ b/extensions/ima/src/test/java/com/google/android/exoplayer2/ext/ima/SingletonImaFactory.java
@@ -0,0 +1,71 @@
+/*
+ * Copyright (C) 2018 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.ima;
+
+import android.content.Context;
+import com.google.ads.interactivemedia.v3.api.AdDisplayContainer;
+import com.google.ads.interactivemedia.v3.api.AdsRenderingSettings;
+import com.google.ads.interactivemedia.v3.api.AdsRequest;
+import com.google.ads.interactivemedia.v3.api.ImaSdkSettings;
+
+/** {@link ImaAdsLoader.ImaFactory} that returns provided instances from each getter, for tests. */
+final class SingletonImaFactory implements ImaAdsLoader.ImaFactory {
+
+  private final ImaSdkSettings imaSdkSettings;
+  private final AdsRenderingSettings adsRenderingSettings;
+  private final AdDisplayContainer adDisplayContainer;
+  private final AdsRequest adsRequest;
+  private final com.google.ads.interactivemedia.v3.api.AdsLoader adsLoader;
+
+  public SingletonImaFactory(
+      ImaSdkSettings imaSdkSettings,
+      AdsRenderingSettings adsRenderingSettings,
+      AdDisplayContainer adDisplayContainer,
+      AdsRequest adsRequest,
+      com.google.ads.interactivemedia.v3.api.AdsLoader adsLoader) {
+    this.imaSdkSettings = imaSdkSettings;
+    this.adsRenderingSettings = adsRenderingSettings;
+    this.adDisplayContainer = adDisplayContainer;
+    this.adsRequest = adsRequest;
+    this.adsLoader = adsLoader;
+  }
+
+  @Override
+  public ImaSdkSettings createImaSdkSettings() {
+    return imaSdkSettings;
+  }
+
+  @Override
+  public AdsRenderingSettings createAdsRenderingSettings() {
+    return adsRenderingSettings;
+  }
+
+  @Override
+  public AdDisplayContainer createAdDisplayContainer() {
+    return adDisplayContainer;
+  }
+
+  @Override
+  public AdsRequest createAdsRequest() {
+    return adsRequest;
+  }
+
+  @Override
+  public com.google.ads.interactivemedia.v3.api.AdsLoader createAdsLoader(
+      Context context, ImaSdkSettings imaSdkSettings) {
+    return adsLoader;
+  }
+}
diff --git a/extensions/ima/src/test/resources/robolectric.properties b/extensions/ima/src/test/resources/robolectric.properties
new file mode 100644
index 0000000000..2f3210368e
--- /dev/null
+++ b/extensions/ima/src/test/resources/robolectric.properties
@@ -0,0 +1 @@
+manifest=src/test/AndroidManifest.xml