Add DownloadState.mergeAction method

This method is needed by DownloadManager.

PiperOrigin-RevId: 232447145

library/core/src/main/java/com/google/android/exoplayer2/offline/DownloadIndexUtil.java

@@ -16,12 +16,7 @@
 package com.google.android.exoplayer2.offline;
 
 import android.support.annotation.Nullable;
-import com.google.android.exoplayer2.C;
-import com.google.android.exoplayer2.offline.DownloadState.State;
-import com.google.android.exoplayer2.util.Assertions;
 import java.io.IOException;
-import java.util.Collections;
-import java.util.HashSet;
 
 /** {@link DownloadIndex} related utility methods. */
 public final class DownloadIndexUtil {
@@ -79,46 +74,10 @@ public final class DownloadIndexUtil {
       DownloadIndex downloadIndex, @Nullable String id, DownloadAction action) {
     DownloadState downloadState = downloadIndex.getDownloadState(id != null ? id : action.id);
     if (downloadState != null) {
-      downloadState = merge(downloadState, action);
+      downloadState = downloadState.mergeAction(action);
     } else {
       downloadState = new DownloadState(action);
     }
     downloadIndex.putDownloadState(downloadState);
   }
-
-  private static DownloadState merge(DownloadState downloadState, DownloadAction action) {
-    Assertions.checkArgument(action.type.equals(downloadState.type));
-    @State int newState;
-    if (action.isRemoveAction) {
-      newState = DownloadState.STATE_REMOVING;
-    } else {
-      if (downloadState.state == DownloadState.STATE_REMOVING
-          || downloadState.state == DownloadState.STATE_RESTARTING) {
-        newState = DownloadState.STATE_RESTARTING;
-      } else if (downloadState.state == DownloadState.STATE_STOPPED) {
-        newState = DownloadState.STATE_STOPPED;
-      } else {
-        newState = DownloadState.STATE_QUEUED;
-      }
-    }
-    HashSet<StreamKey> keys = new HashSet<>(action.keys);
-    Collections.addAll(keys, downloadState.streamKeys);
-    StreamKey[] newKeys = keys.toArray(new StreamKey[0]);
-    return new DownloadState(
-        downloadState.id,
-        downloadState.type,
-        action.uri,
-        action.customCacheKey,
-        newState,
-        /* downloadPercentage= */ C.PERCENTAGE_UNSET,
-        downloadState.downloadedBytes,
-        /* totalBytes= */ C.LENGTH_UNSET,
-        downloadState.failureReason,
-        downloadState.stopFlags,
-        downloadState.notMetRequirements,
-        downloadState.startTimeMs,
-        downloadState.updateTimeMs,
-        newKeys,
-        action.data);
-  }
 }

library/core/src/main/java/com/google/android/exoplayer2/offline/DownloadState.java

@@ -24,6 +24,8 @@ import com.google.android.exoplayer2.util.Assertions;
 import java.lang.annotation.Documented;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
+import java.util.Collections;
+import java.util.HashSet;
 
 /** Represents state of a download. */
 public final class DownloadState {
@@ -231,4 +233,62 @@ public final class DownloadState {
     this.streamKeys = streamKeys;
     this.customMetadata = customMetadata;
   }
+
+  /**
+   * Merges the given {@link DownloadAction} and creates a new {@link DownloadState}. The action
+   * must have the same id and type.
+   *
+   * @param action The {@link DownloadAction} to be merged.
+   * @return A new {@link DownloadState}.
+   */
+  public DownloadState mergeAction(DownloadAction action) {
+    Assertions.checkArgument(action.id.equals(id));
+    Assertions.checkArgument(action.type.equals(type));
+    return new DownloadState(
+        id,
+        type,
+        action.uri,
+        action.customCacheKey,
+        getNextState(action, state),
+        /* downloadPercentage= */ C.PERCENTAGE_UNSET,
+        downloadedBytes,
+        /* totalBytes= */ C.LENGTH_UNSET,
+        FAILURE_REASON_NONE,
+        stopFlags,
+        notMetRequirements,
+        startTimeMs,
+        updateTimeMs,
+        mergeStreamKeys(this, action),
+        action.data);
+  }
+
+  private static int getNextState(DownloadAction action, int currentState) {
+    int newState;
+    if (action.isRemoveAction) {
+      newState = STATE_REMOVING;
+    } else {
+      if (currentState == STATE_REMOVING || currentState == STATE_RESTARTING) {
+        newState = STATE_RESTARTING;
+      } else if (currentState == STATE_STOPPED) {
+        newState = STATE_STOPPED;
+      } else {
+        newState = STATE_QUEUED;
+      }
+    }
+    return newState;
+  }
+
+  private static StreamKey[] mergeStreamKeys(DownloadState downloadState, DownloadAction action) {
+    StreamKey[] streamKeys = downloadState.streamKeys;
+    if (!action.isRemoveAction && streamKeys.length > 0) {
+      if (action.keys.isEmpty()) {
+        streamKeys = new StreamKey[0];
+      } else {
+        HashSet<StreamKey> keys = new HashSet<>(action.keys);
+        Collections.addAll(keys, downloadState.streamKeys);
+        streamKeys = keys.toArray(new StreamKey[0]);
+      }
+    }
+    return streamKeys;
+  }
 }

library/core/src/test/java/com/google/android/exoplayer2/offline/DefaultDownloadIndexTest.java

@@ -18,12 +18,8 @@ package com.google.android.exoplayer2.offline;
 import static com.google.common.truth.Truth.assertThat;
 
 import android.database.sqlite.SQLiteDatabase;
-import android.net.Uri;
-import android.support.annotation.Nullable;
-import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.database.ExoDatabaseProvider;
 import com.google.android.exoplayer2.database.VersionTable;
-import java.util.Arrays;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
@@ -62,7 +58,7 @@ public class DefaultDownloadIndexTest {
     downloadIndex.putDownloadState(downloadState);
     DownloadState readDownloadState = downloadIndex.getDownloadState(id);
 
-    assertEqual(readDownloadState, downloadState);
+    DownloadStateTest.assertEqual(readDownloadState, downloadState);
   }
 
   @Test
@@ -94,7 +90,7 @@ public class DefaultDownloadIndexTest {
     DownloadState readDownloadState = downloadIndex.getDownloadState(id);
 
     assertThat(readDownloadState).isNotNull();
-    assertEqual(readDownloadState, downloadState);
+    DownloadStateTest.assertEqual(readDownloadState, downloadState);
   }
 
   @Test
@@ -106,7 +102,7 @@ public class DefaultDownloadIndexTest {
     downloadIndex = new DefaultDownloadIndex(databaseProvider);
     DownloadState readDownloadState = downloadIndex.getDownloadState(id);
     assertThat(readDownloadState).isNotNull();
-    assertEqual(readDownloadState, downloadState);
+    DownloadStateTest.assertEqual(readDownloadState, downloadState);
   }
 
   @Test
@@ -141,9 +137,9 @@ public class DefaultDownloadIndexTest {
 
     assertThat(cursor.getCount()).isEqualTo(2);
     cursor.moveToNext();
-    assertEqual(cursor.getDownloadState(), downloadState2);
+    DownloadStateTest.assertEqual(cursor.getDownloadState(), downloadState2);
     cursor.moveToNext();
-    assertEqual(cursor.getDownloadState(), downloadState1);
+    DownloadStateTest.assertEqual(cursor.getDownloadState(), downloadState1);
     cursor.close();
   }
 
@@ -173,9 +169,9 @@ public class DefaultDownloadIndexTest {
 
     assertThat(cursor.getCount()).isEqualTo(2);
     cursor.moveToNext();
-    assertEqual(cursor.getDownloadState(), downloadState1);
+    DownloadStateTest.assertEqual(cursor.getDownloadState(), downloadState1);
     cursor.moveToNext();
-    assertEqual(cursor.getDownloadState(), downloadState3);
+    DownloadStateTest.assertEqual(cursor.getDownloadState(), downloadState3);
     cursor.close();
   }
 
@@ -211,184 +207,4 @@ public class DefaultDownloadIndexTest {
         .isEqualTo(DefaultDownloadIndex.TABLE_VERSION);
   }
 
-  private static void assertEqual(DownloadState downloadState, DownloadState expected) {
-    assertThat(areEqual(downloadState, expected)).isTrue();
-  }
-
-  private static boolean areEqual(DownloadState downloadState, DownloadState that) {
-    if (downloadState.state != that.state) {
-      return false;
-    }
-    if (Float.compare(that.downloadPercentage, downloadState.downloadPercentage) != 0) {
-      return false;
-    }
-    if (downloadState.downloadedBytes != that.downloadedBytes) {
-      return false;
-    }
-    if (downloadState.totalBytes != that.totalBytes) {
-      return false;
-    }
-    if (downloadState.startTimeMs != that.startTimeMs) {
-      return false;
-    }
-    if (downloadState.updateTimeMs != that.updateTimeMs) {
-      return false;
-    }
-    if (downloadState.failureReason != that.failureReason) {
-      return false;
-    }
-    if (downloadState.stopFlags != that.stopFlags) {
-      return false;
-    }
-    if (downloadState.notMetRequirements != that.notMetRequirements) {
-      return false;
-    }
-    if (!downloadState.id.equals(that.id)) {
-      return false;
-    }
-    if (!downloadState.type.equals(that.type)) {
-      return false;
-    }
-    if (!downloadState.uri.equals(that.uri)) {
-      return false;
-    }
-    if (downloadState.cacheKey != null
-        ? !downloadState.cacheKey.equals(that.cacheKey)
-        : that.cacheKey != null) {
-      return false;
-    }
-    if (!Arrays.equals(downloadState.streamKeys, that.streamKeys)) {
-      return false;
-    }
-    return Arrays.equals(downloadState.customMetadata, that.customMetadata);
-  }
-
-  private static class DownloadStateBuilder {
-    private String id;
-    private String type;
-    private String uri;
-    @Nullable private String cacheKey;
-    private int state;
-    private float downloadPercentage;
-    private long downloadedBytes;
-    private long totalBytes;
-    private int failureReason;
-    private int stopFlags;
-    private int notMetRequirements;
-    private long startTimeMs;
-    private long updateTimeMs;
-    private StreamKey[] streamKeys;
-    private byte[] customMetadata;
-
-    private DownloadStateBuilder(String id) {
-      this.id = id;
-      this.type = "type";
-      this.uri = "uri";
-      this.cacheKey = null;
-      this.state = DownloadState.STATE_QUEUED;
-      this.downloadPercentage = (float) C.PERCENTAGE_UNSET;
-      this.downloadedBytes = (long) 0;
-      this.totalBytes = (long) C.LENGTH_UNSET;
-      this.failureReason = DownloadState.FAILURE_REASON_NONE;
-      this.stopFlags = 0;
-      this.startTimeMs = (long) 0;
-      this.updateTimeMs = (long) 0;
-      this.streamKeys = new StreamKey[0];
-      this.customMetadata = new byte[0];
-    }
-
-    public DownloadStateBuilder setId(String id) {
-      this.id = id;
-      return this;
-    }
-
-    public DownloadStateBuilder setType(String type) {
-      this.type = type;
-      return this;
-    }
-
-    public DownloadStateBuilder setUri(String uri) {
-      this.uri = uri;
-      return this;
-    }
-
-    public DownloadStateBuilder setCacheKey(@Nullable String cacheKey) {
-      this.cacheKey = cacheKey;
-      return this;
-    }
-
-    public DownloadStateBuilder setState(int state) {
-      this.state = state;
-      return this;
-    }
-
-    public DownloadStateBuilder setDownloadPercentage(float downloadPercentage) {
-      this.downloadPercentage = downloadPercentage;
-      return this;
-    }
-
-    public DownloadStateBuilder setDownloadedBytes(long downloadedBytes) {
-      this.downloadedBytes = downloadedBytes;
-      return this;
-    }
-
-    public DownloadStateBuilder setTotalBytes(long totalBytes) {
-      this.totalBytes = totalBytes;
-      return this;
-    }
-
-    public DownloadStateBuilder setFailureReason(int failureReason) {
-      this.failureReason = failureReason;
-      return this;
-    }
-
-    public DownloadStateBuilder setStopFlags(int stopFlags) {
-      this.stopFlags = stopFlags;
-      return this;
-    }
-
-    public DownloadStateBuilder setNotMetRequirements(int notMetRequirements) {
-      this.notMetRequirements = notMetRequirements;
-      return this;
-    }
-
-    public DownloadStateBuilder setStartTimeMs(long startTimeMs) {
-      this.startTimeMs = startTimeMs;
-      return this;
-    }
-
-    public DownloadStateBuilder setUpdateTimeMs(long updateTimeMs) {
-      this.updateTimeMs = updateTimeMs;
-      return this;
-    }
-
-    public DownloadStateBuilder setStreamKeys(StreamKey... streamKeys) {
-      this.streamKeys = streamKeys;
-      return this;
-    }
-
-    public DownloadStateBuilder setCustomMetadata(byte[] customMetadata) {
-      this.customMetadata = customMetadata;
-      return this;
-    }
-
-    public DownloadState build() {
-      return new DownloadState(
-          id,
-          type,
-          Uri.parse(uri),
-          cacheKey,
-          state,
-          downloadPercentage,
-          downloadedBytes,
-          totalBytes,
-          failureReason,
-          stopFlags,
-          notMetRequirements,
-          startTimeMs,
-          updateTimeMs,
-          streamKeys,
-          customMetadata);
-    }
-  }
 }

library/core/src/test/java/com/google/android/exoplayer2/offline/DownloadStateBuilder.java

@@ -0,0 +1,181 @@
+/*
+ * 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.offline;
+
+import android.net.Uri;
+import android.support.annotation.Nullable;
+import com.google.android.exoplayer2.C;
+
+/**
+ * Builder for DownloadState.
+ *
+ * <p>Defines default values for each field (except {@code id}) to facilitate DownloadState creation
+ * for tests. Tests must avoid depending on the default values but explicitly set tested parameters
+ * during test initialization.
+ */
+class DownloadStateBuilder {
+  private String id;
+  private String type;
+  private Uri uri;
+  @Nullable private String cacheKey;
+  private int state;
+  private float downloadPercentage;
+  private long downloadedBytes;
+  private long totalBytes;
+  private int failureReason;
+  private int stopFlags;
+  private int notMetRequirements;
+  private long startTimeMs;
+  private long updateTimeMs;
+  private StreamKey[] streamKeys;
+  private byte[] customMetadata;
+
+  DownloadStateBuilder(String id) {
+    this(id, "type", Uri.parse("uri"), /* cacheKey= */ null, new byte[0], new StreamKey[0]);
+  }
+
+  DownloadStateBuilder(DownloadAction action) {
+    this(
+        action.id,
+        action.type,
+        action.uri,
+        action.customCacheKey,
+        action.data,
+        action.keys.toArray(new StreamKey[0]));
+  }
+
+  DownloadStateBuilder(
+      String id,
+      String type,
+      Uri uri,
+      String cacheKey,
+      byte[] customMetadata,
+      StreamKey[] streamKeys) {
+    this.id = id;
+    this.type = type;
+    this.uri = uri;
+    this.cacheKey = cacheKey;
+    this.state = DownloadState.STATE_QUEUED;
+    this.downloadPercentage = (float) C.PERCENTAGE_UNSET;
+    this.downloadedBytes = (long) 0;
+    this.totalBytes = (long) C.LENGTH_UNSET;
+    this.failureReason = DownloadState.FAILURE_REASON_NONE;
+    this.stopFlags = 0;
+    this.startTimeMs = (long) 0;
+    this.updateTimeMs = (long) 0;
+    this.streamKeys = streamKeys;
+    this.customMetadata = customMetadata;
+  }
+
+  public DownloadStateBuilder setId(String id) {
+    this.id = id;
+    return this;
+  }
+
+  public DownloadStateBuilder setType(String type) {
+    this.type = type;
+    return this;
+  }
+
+  public DownloadStateBuilder setUri(String uri) {
+    this.uri = Uri.parse(uri);
+    return this;
+  }
+
+  public DownloadStateBuilder setUri(Uri uri) {
+    this.uri = uri;
+    return this;
+  }
+
+  public DownloadStateBuilder setCacheKey(@Nullable String cacheKey) {
+    this.cacheKey = cacheKey;
+    return this;
+  }
+
+  public DownloadStateBuilder setState(int state) {
+    this.state = state;
+    return this;
+  }
+
+  public DownloadStateBuilder setDownloadPercentage(float downloadPercentage) {
+    this.downloadPercentage = downloadPercentage;
+    return this;
+  }
+
+  public DownloadStateBuilder setDownloadedBytes(long downloadedBytes) {
+    this.downloadedBytes = downloadedBytes;
+    return this;
+  }
+
+  public DownloadStateBuilder setTotalBytes(long totalBytes) {
+    this.totalBytes = totalBytes;
+    return this;
+  }
+
+  public DownloadStateBuilder setFailureReason(int failureReason) {
+    this.failureReason = failureReason;
+    return this;
+  }
+
+  public DownloadStateBuilder setStopFlags(int stopFlags) {
+    this.stopFlags = stopFlags;
+    return this;
+  }
+
+  public DownloadStateBuilder setNotMetRequirements(int notMetRequirements) {
+    this.notMetRequirements = notMetRequirements;
+    return this;
+  }
+
+  public DownloadStateBuilder setStartTimeMs(long startTimeMs) {
+    this.startTimeMs = startTimeMs;
+    return this;
+  }
+
+  public DownloadStateBuilder setUpdateTimeMs(long updateTimeMs) {
+    this.updateTimeMs = updateTimeMs;
+    return this;
+  }
+
+  public DownloadStateBuilder setStreamKeys(StreamKey... streamKeys) {
+    this.streamKeys = streamKeys;
+    return this;
+  }
+
+  public DownloadStateBuilder setCustomMetadata(byte[] customMetadata) {
+    this.customMetadata = customMetadata;
+    return this;
+  }
+
+  public DownloadState build() {
+    return new DownloadState(
+        id,
+        type,
+        uri,
+        cacheKey,
+        state,
+        downloadPercentage,
+        downloadedBytes,
+        totalBytes,
+        failureReason,
+        stopFlags,
+        notMetRequirements,
+        startTimeMs,
+        updateTimeMs,
+        streamKeys,
+        customMetadata);
+  }
+}

library/core/src/test/java/com/google/android/exoplayer2/offline/DownloadStateTest.java

@@ -0,0 +1,344 @@
+/*
+ * 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.offline;
+
+import static com.google.common.truth.Truth.assertThat;
+import static org.junit.Assert.fail;
+
+import android.net.Uri;
+import java.util.Arrays;
+import java.util.Collections;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+
+/** Unit tests for {@link DownloadState}. */
+@RunWith(RobolectricTestRunner.class)
+public class DownloadStateTest {
+
+  private Uri testUri;
+
+  @Before
+  public void setUp() throws Exception {
+    testUri = Uri.parse("https://www.test.com/download1");
+  }
+
+  @Test
+  public void mergeAction_actionHaveDifferentType_throwsException() {
+    DownloadAction downloadAction = createDownloadAction();
+    DownloadState downloadState =
+        new DownloadStateBuilder(downloadAction)
+            .setType(downloadAction.type + "_different")
+            .setState(DownloadState.STATE_QUEUED)
+            .build();
+
+    try {
+      downloadState.mergeAction(downloadAction);
+      fail();
+    } catch (Exception e) {
+      // Expected.
+    }
+  }
+
+  @Test
+  public void mergeAction_actionHaveDifferentId_throwsException() {
+    DownloadAction downloadAction = createDownloadAction();
+    DownloadState downloadState =
+        new DownloadStateBuilder(downloadAction)
+            .setId(downloadAction.id + "_different")
+            .setState(DownloadState.STATE_QUEUED)
+            .build();
+
+    try {
+      downloadState.mergeAction(downloadAction);
+      fail();
+    } catch (Exception e) {
+      // Expected.
+    }
+  }
+
+  @Test
+  public void mergeAction_actionsWithSameIdAndType_doesNotFail() {
+    DownloadAction downloadAction = createDownloadAction();
+    DownloadStateBuilder downloadStateBuilder =
+        new DownloadStateBuilder(downloadAction).setState(DownloadState.STATE_QUEUED);
+    DownloadState downloadState = downloadStateBuilder.build();
+
+    downloadState.mergeAction(downloadAction);
+  }
+
+  @Test
+  public void mergeAction_actionHaveDifferentUri_downloadStateUriIsUpdated() {
+    DownloadAction downloadAction = createDownloadAction();
+    DownloadStateBuilder downloadStateBuilder =
+        new DownloadStateBuilder(downloadAction)
+            .setUri(downloadAction.uri + "_different")
+            .setState(DownloadState.STATE_QUEUED);
+    DownloadState downloadState = downloadStateBuilder.build();
+
+    DownloadState mergedDownloadState = downloadState.mergeAction(downloadAction);
+
+    DownloadState expectedDownloadState = downloadStateBuilder.setUri(downloadAction.uri).build();
+    assertEqual(mergedDownloadState, expectedDownloadState);
+  }
+
+  @Test
+  public void mergeAction_actionHaveDifferentData_downloadStateDataIsUpdated() {
+    DownloadAction downloadAction =
+        DownloadAction.createDownloadAction(
+            DownloadAction.TYPE_DASH,
+            testUri,
+            Collections.emptyList(),
+            /* customCacheKey= */ null,
+            /* data= */ new byte[] {1, 2, 3, 4});
+    DownloadStateBuilder downloadStateBuilder =
+        new DownloadStateBuilder(downloadAction)
+            .setState(DownloadState.STATE_QUEUED)
+            .setCustomMetadata(new byte[0]);
+    DownloadState downloadState = downloadStateBuilder.build();
+
+    DownloadState mergedDownloadState = downloadState.mergeAction(downloadAction);
+
+    DownloadState expectedDownloadState =
+        downloadStateBuilder.setCustomMetadata(downloadAction.data).build();
+    assertEqual(mergedDownloadState, expectedDownloadState);
+  }
+
+  @Test
+  public void mergeAction_queuedDownloadRemoveAction_stateBecomesRemoving() {
+    DownloadAction downloadAction = createRemoveAction();
+    DownloadStateBuilder downloadStateBuilder =
+        new DownloadStateBuilder(downloadAction).setState(DownloadState.STATE_QUEUED);
+    DownloadState downloadState = downloadStateBuilder.build();
+
+    DownloadState mergedDownloadState = downloadState.mergeAction(downloadAction);
+
+    DownloadState expectedDownloadState =
+        downloadStateBuilder.setState(DownloadState.STATE_REMOVING).build();
+    assertEqual(mergedDownloadState, expectedDownloadState);
+  }
+
+  @Test
+  public void mergeAction_removingDownloadDownloadAction_stateBecomesRestarting() {
+    DownloadAction downloadAction = createDownloadAction();
+    DownloadStateBuilder downloadStateBuilder =
+        new DownloadStateBuilder(downloadAction).setState(DownloadState.STATE_REMOVING);
+    DownloadState downloadState = downloadStateBuilder.build();
+
+    DownloadState mergedDownloadState = downloadState.mergeAction(downloadAction);
+
+    DownloadState expectedDownloadState =
+        downloadStateBuilder.setState(DownloadState.STATE_RESTARTING).build();
+    assertEqual(mergedDownloadState, expectedDownloadState);
+  }
+
+  @Test
+  public void mergeAction_failedDownloadDownloadAction_stateBecomesQueued() {
+    DownloadAction downloadAction = createDownloadAction();
+    DownloadStateBuilder downloadStateBuilder =
+        new DownloadStateBuilder(downloadAction)
+            .setState(DownloadState.STATE_FAILED)
+            .setFailureReason(DownloadState.FAILURE_REASON_UNKNOWN);
+    DownloadState downloadState = downloadStateBuilder.build();
+
+    DownloadState mergedDownloadState = downloadState.mergeAction(downloadAction);
+
+    DownloadState expectedDownloadState =
+        downloadStateBuilder
+            .setState(DownloadState.STATE_QUEUED)
+            .setFailureReason(DownloadState.FAILURE_REASON_NONE)
+            .build();
+    assertEqual(mergedDownloadState, expectedDownloadState);
+  }
+
+  @Test
+  public void mergeAction_stoppedDownloadDownloadAction_stateStaysStopped() {
+    DownloadAction downloadAction = createDownloadAction();
+    DownloadStateBuilder downloadStateBuilder =
+        new DownloadStateBuilder(downloadAction)
+            .setState(DownloadState.STATE_STOPPED)
+            .setStopFlags(DownloadState.STOP_FLAG_STOPPED);
+    DownloadState downloadState = downloadStateBuilder.build();
+
+    DownloadState mergedDownloadState = downloadState.mergeAction(downloadAction);
+
+    assertEqual(mergedDownloadState, downloadState);
+  }
+
+  @Test
+  public void mergeAction_stoppedDownloadRemoveAction_stateBecomesRemoving() {
+    DownloadAction downloadAction = createRemoveAction();
+    DownloadStateBuilder downloadStateBuilder =
+        new DownloadStateBuilder(downloadAction)
+            .setState(DownloadState.STATE_STOPPED)
+            .setStopFlags(DownloadState.STOP_FLAG_STOPPED);
+    DownloadState downloadState = downloadStateBuilder.build();
+
+    DownloadState mergedDownloadState = downloadState.mergeAction(downloadAction);
+
+    DownloadState expectedDownloadState =
+        downloadStateBuilder.setState(DownloadState.STATE_REMOVING).build();
+    assertEqual(mergedDownloadState, expectedDownloadState);
+  }
+
+  @Test
+  public void mergeAction_restartingDownloadRemoveAction_stateBecomesRemoving() {
+    DownloadAction downloadAction = createRemoveAction();
+    DownloadStateBuilder downloadStateBuilder =
+        new DownloadStateBuilder(downloadAction).setState(DownloadState.STATE_RESTARTING);
+    DownloadState downloadState = downloadStateBuilder.build();
+
+    DownloadState mergedDownloadState = downloadState.mergeAction(downloadAction);
+
+    DownloadState expectedDownloadState =
+        downloadStateBuilder.setState(DownloadState.STATE_REMOVING).build();
+    assertEqual(mergedDownloadState, expectedDownloadState);
+  }
+
+  @Test
+  public void mergeAction_returnsMergedKeys() {
+    StreamKey streamKey1 = new StreamKey(/* groupIndex= */ 0, /* trackIndex= */ 0);
+    StreamKey streamKey2 = new StreamKey(/* groupIndex= */ 1, /* trackIndex= */ 1);
+    StreamKey[] keys1 = new StreamKey[] {streamKey1};
+    StreamKey[] keys2 = new StreamKey[] {streamKey2};
+    StreamKey[] expectedKeys = new StreamKey[] {streamKey1, streamKey2};
+
+    doTestMergeActionReturnsMergedKeys(keys1, keys2, expectedKeys);
+  }
+
+  @Test
+  public void mergeAction_returnsUniqueKeys() {
+    StreamKey streamKey1 = new StreamKey(/* groupIndex= */ 0, /* trackIndex= */ 0);
+    StreamKey streamKey1Copy = new StreamKey(/* groupIndex= */ 0, /* trackIndex= */ 0);
+    StreamKey streamKey2 = new StreamKey(/* groupIndex= */ 1, /* trackIndex= */ 1);
+    StreamKey[] keys1 = new StreamKey[] {streamKey1};
+    StreamKey[] keys2 = new StreamKey[] {streamKey2, streamKey1Copy};
+    StreamKey[] expectedKeys = new StreamKey[] {streamKey1, streamKey2};
+
+    doTestMergeActionReturnsMergedKeys(keys1, keys2, expectedKeys);
+  }
+
+  @Test
+  public void mergeAction_ifFirstActionKeysEmpty_returnsEmptyKeys() {
+    StreamKey streamKey1 = new StreamKey(/* groupIndex= */ 0, /* trackIndex= */ 0);
+    StreamKey streamKey2 = new StreamKey(/* groupIndex= */ 1, /* trackIndex= */ 1);
+    StreamKey[] keys1 = new StreamKey[] {};
+    StreamKey[] keys2 = new StreamKey[] {streamKey2, streamKey1};
+    StreamKey[] expectedKeys = new StreamKey[] {};
+
+    doTestMergeActionReturnsMergedKeys(keys1, keys2, expectedKeys);
+  }
+
+  @Test
+  public void mergeAction_ifNotFirstActionKeysEmpty_returnsEmptyKeys() {
+    StreamKey streamKey1 = new StreamKey(/* groupIndex= */ 0, /* trackIndex= */ 0);
+    StreamKey streamKey2 = new StreamKey(/* groupIndex= */ 1, /* trackIndex= */ 1);
+    StreamKey[] keys1 = new StreamKey[] {streamKey2, streamKey1};
+    StreamKey[] keys2 = new StreamKey[] {};
+    StreamKey[] expectedKeys = new StreamKey[] {};
+
+    doTestMergeActionReturnsMergedKeys(keys1, keys2, expectedKeys);
+  }
+
+  private void doTestMergeActionReturnsMergedKeys(
+      StreamKey[] keys1, StreamKey[] keys2, StreamKey[] expectedKeys) {
+    DownloadAction downloadAction =
+        DownloadAction.createDownloadAction(
+            DownloadAction.TYPE_DASH,
+            testUri,
+            Arrays.asList(keys2),
+            /* customCacheKey= */ null,
+            /* data= */ null);
+    DownloadStateBuilder downloadStateBuilder =
+        new DownloadStateBuilder(downloadAction)
+            .setState(DownloadState.STATE_QUEUED)
+            .setStreamKeys(keys1);
+    DownloadState downloadState = downloadStateBuilder.build();
+
+    DownloadState mergedDownloadState = downloadState.mergeAction(downloadAction);
+
+    DownloadState expectedDownloadState = downloadStateBuilder.setStreamKeys(expectedKeys).build();
+    assertEqual(mergedDownloadState, expectedDownloadState);
+  }
+
+  static void assertEqual(DownloadState downloadState, DownloadState expected) {
+    assertThat(areEqual(downloadState, expected)).isTrue();
+  }
+
+  private static boolean areEqual(DownloadState downloadState, DownloadState that) {
+    if (downloadState.state != that.state) {
+      return false;
+    }
+    if (Float.compare(that.downloadPercentage, downloadState.downloadPercentage) != 0) {
+      return false;
+    }
+    if (downloadState.downloadedBytes != that.downloadedBytes) {
+      return false;
+    }
+    if (downloadState.totalBytes != that.totalBytes) {
+      return false;
+    }
+    if (downloadState.startTimeMs != that.startTimeMs) {
+      return false;
+    }
+    if (downloadState.updateTimeMs != that.updateTimeMs) {
+      return false;
+    }
+    if (downloadState.failureReason != that.failureReason) {
+      return false;
+    }
+    if (downloadState.stopFlags != that.stopFlags) {
+      return false;
+    }
+    if (downloadState.notMetRequirements != that.notMetRequirements) {
+      return false;
+    }
+    if (!downloadState.id.equals(that.id)) {
+      return false;
+    }
+    if (!downloadState.type.equals(that.type)) {
+      return false;
+    }
+    if (!downloadState.uri.equals(that.uri)) {
+      return false;
+    }
+    if (downloadState.cacheKey != null
+        ? !downloadState.cacheKey.equals(that.cacheKey)
+        : that.cacheKey != null) {
+      return false;
+    }
+    if (downloadState.streamKeys.length != that.streamKeys.length
+        || !Arrays.asList(downloadState.streamKeys).containsAll(Arrays.asList(that.streamKeys))) {
+      return false;
+    }
+    return Arrays.equals(downloadState.customMetadata, that.customMetadata);
+  }
+
+  private DownloadAction createDownloadAction() {
+    return DownloadAction.createDownloadAction(
+        DownloadAction.TYPE_DASH,
+        testUri,
+        Collections.emptyList(),
+        /* customCacheKey= */ null,
+        /* data= */ null);
+  }
+
+  private DownloadAction createRemoveAction() {
+    return DownloadAction.createRemoveAction(
+        DownloadAction.TYPE_DASH, testUri, /* customCacheKey= */ null);
+  }
+}