Make FakeDataSource able to serve multiple fake files

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=150748155

library/core/src/androidTest/java/com/google/android/exoplayer2/extractor/DefaultExtractorInputTest.java

@@ -269,9 +269,8 @@ public class DefaultExtractorInputTest extends TestCase {
   public void testSkipFullyLarge() throws Exception {
     // Tests skipping an amount of data that's larger than any internal scratch space.
     int largeSkipSize = 1024 * 1024;
-    FakeDataSource.Builder builder = new FakeDataSource.Builder();
-    builder.appendReadData(new byte[largeSkipSize]);
-    FakeDataSource testDataSource = builder.build();
+    FakeDataSource testDataSource = new FakeDataSource();
+    testDataSource.getDataSet().newDefaultData().appendReadData(new byte[largeSkipSize]);
     testDataSource.open(new DataSpec(Uri.parse(TEST_URI)));
 
     DefaultExtractorInput input = new DefaultExtractorInput(testDataSource, 0, C.LENGTH_UNSET);
@@ -397,29 +396,29 @@ public class DefaultExtractorInputTest extends TestCase {
   }
 
   private static FakeDataSource buildDataSource() throws Exception {
-    FakeDataSource.Builder builder = new FakeDataSource.Builder();
-    builder.appendReadData(Arrays.copyOfRange(TEST_DATA, 0, 3));
-    builder.appendReadData(Arrays.copyOfRange(TEST_DATA, 3, 6));
-    builder.appendReadData(Arrays.copyOfRange(TEST_DATA, 6, 9));
-    FakeDataSource testDataSource = builder.build();
+    FakeDataSource testDataSource = new FakeDataSource();
+    testDataSource.getDataSet().newDefaultData()
+        .appendReadData(Arrays.copyOfRange(TEST_DATA, 0, 3))
+        .appendReadData(Arrays.copyOfRange(TEST_DATA, 3, 6))
+        .appendReadData(Arrays.copyOfRange(TEST_DATA, 6, 9));
     testDataSource.open(new DataSpec(Uri.parse(TEST_URI)));
     return testDataSource;
   }
 
   private static FakeDataSource buildFailingDataSource() throws Exception {
-    FakeDataSource.Builder builder = new FakeDataSource.Builder();
-    builder.appendReadData(Arrays.copyOfRange(TEST_DATA, 0, 6));
-    builder.appendReadError(new IOException());
-    builder.appendReadData(Arrays.copyOfRange(TEST_DATA, 6, 9));
-    FakeDataSource testDataSource = builder.build();
+    FakeDataSource testDataSource = new FakeDataSource();
+    testDataSource.getDataSet().newDefaultData()
+        .appendReadData(Arrays.copyOfRange(TEST_DATA, 0, 6))
+        .appendReadError(new IOException())
+        .appendReadData(Arrays.copyOfRange(TEST_DATA, 6, 9));
     testDataSource.open(new DataSpec(Uri.parse(TEST_URI)));
     return testDataSource;
   }
 
   private static FakeDataSource buildLargeDataSource() throws Exception {
-    FakeDataSource.Builder builder = new FakeDataSource.Builder();
-    builder.appendReadData(new byte[LARGE_TEST_DATA_LENGTH]);
-    FakeDataSource testDataSource = builder.build();
+    FakeDataSource testDataSource = new FakeDataSource();
+    testDataSource.getDataSet().newDefaultData()
+        .appendReadData(new byte[LARGE_TEST_DATA_LENGTH]);
     testDataSource.open(new DataSpec(Uri.parse(TEST_URI)));
     return testDataSource;
   }

library/core/src/androidTest/java/com/google/android/exoplayer2/upstream/DataSourceInputStreamTest.java

@@ -15,6 +15,7 @@
  */
 package com.google.android.exoplayer2.upstream;
 
+import android.net.Uri;
 import android.test.MoreAsserts;
 import com.google.android.exoplayer2.testutil.FakeDataSource;
 import com.google.android.exoplayer2.testutil.TestUtil;
@@ -88,12 +89,13 @@ public class DataSourceInputStreamTest extends TestCase {
   }
 
   private static DataSourceInputStream buildTestInputStream() {
-    FakeDataSource.Builder fakeDataSourceBuilder = new FakeDataSource.Builder()
+    FakeDataSource fakeDataSource = new FakeDataSource();
+    fakeDataSource.getDataSet().newDefaultData()
         .appendReadData(Arrays.copyOfRange(TEST_DATA, 0, 5))
         .appendReadData(Arrays.copyOfRange(TEST_DATA, 5, 10))
         .appendReadData(Arrays.copyOfRange(TEST_DATA, 10, 15))
         .appendReadData(Arrays.copyOfRange(TEST_DATA, 15, TEST_DATA.length));
-    return new DataSourceInputStream(fakeDataSourceBuilder.build(), new DataSpec(null));
+    return new DataSourceInputStream(fakeDataSource, new DataSpec(Uri.EMPTY));
   }
 
 }

library/core/src/androidTest/java/com/google/android/exoplayer2/upstream/cache/CacheDataSourceTest.java

@@ -20,6 +20,7 @@ import android.test.InstrumentationTestCase;
 import android.test.MoreAsserts;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.testutil.FakeDataSource;
+import com.google.android.exoplayer2.testutil.FakeDataSource.FakeData;
 import com.google.android.exoplayer2.upstream.DataSpec;
 import com.google.android.exoplayer2.upstream.FileDataSource;
 import com.google.android.exoplayer2.util.Util;
@@ -197,12 +198,12 @@ public class CacheDataSourceTest extends InstrumentationTestCase {
   private CacheDataSource createCacheDataSource(boolean setReadException,
       boolean simulateUnknownLength, @CacheDataSource.Flags int flags,
       CacheDataSink cacheWriteDataSink) {
-    FakeDataSource.Builder builder = new FakeDataSource.Builder();
+    FakeDataSource upstream = new FakeDataSource();
+    FakeData fakeData = upstream.getDataSet().newDefaultData()
+        .setSimulateUnknownLength(simulateUnknownLength).appendReadData(TEST_DATA);
     if (setReadException) {
-      builder.appendReadError(new IOException("Shouldn't read from upstream"));
+      fakeData.appendReadError(new IOException("Shouldn't read from upstream"));
     }
-    FakeDataSource upstream =
-        builder.setSimulateUnknownLength(simulateUnknownLength).appendReadData(TEST_DATA).build();
     return new CacheDataSource(simpleCache, upstream, new FileDataSource(), cacheWriteDataSink,
         flags, null);
   }

library/core/src/androidTest/java/com/google/android/exoplayer2/upstream/cache/CacheDataSourceTest2.java

@@ -139,7 +139,9 @@ public class CacheDataSourceTest2 extends AndroidTestCase {
   }
 
   private static FakeDataSource buildFakeUpstreamSource() {
-    return new FakeDataSource.Builder().appendReadData(DATA).build();
+    FakeDataSource fakeDataSource = new FakeDataSource();
+    fakeDataSource.getDataSet().newDefaultData().appendReadData(DATA);
+    return fakeDataSource;
   }
 
   private static CacheDataSource buildCacheDataSource(Context context, DataSource upstreamSource,

testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeDataSource.java

@@ -23,43 +23,79 @@ import com.google.android.exoplayer2.upstream.DataSpec;
 import com.google.android.exoplayer2.util.Assertions;
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.HashMap;
 
 /**
- * A fake {@link DataSource} capable of simulating various scenarios.
- * <p>
- * The data that will be read from the source can be constructed by calling
- * {@link Builder#appendReadData(byte[])}. Calls to {@link #read(byte[], int, int)} will not span
- * the boundaries between arrays passed to successive calls, and hence the boundaries control the
+ * A fake {@link DataSource} capable of simulating various scenarios. It uses a {@link FakeDataSet}
+ * instance which determines the response to data access calls.
+ *
+ * <p>Multiple fake data can be defined by {@link FakeDataSet#setData(String, byte[])} and {@link
+ * FakeDataSet#newData(String)} methods. It's also possible to define a default data by {@link
+ * FakeDataSet#newDefaultData()}.
+ *
+ * <p>{@link FakeDataSet#newData(String)} and {@link FakeDataSet#newDefaultData()} return a {@link
+ * FakeData} instance which can be used to define specific results during {@link #read(byte[], int,
+ * int)} calls.
+ *
+ * <p>The data that will be read from the source can be constructed by calling {@link
+ * FakeData#appendReadData(byte[])} Calls to {@link #read(byte[], int, int)} will not span the
+ * boundaries between arrays passed to successive calls, and hence the boundaries control the
  * positions at which read requests to the source may only be partially satisfied.
- * <p>
- * Errors can be inserted by calling {@link Builder#appendReadError(IOException)}. An inserted error
- * will be thrown from the first call to {@link #read(byte[], int, int)} that attempts to read from
- * the corresponding position, and from all subsequent calls to {@link #read(byte[], int, int)}
+ *
+ * <p>Errors can be inserted by calling {@link FakeData#appendReadError(IOException)}. An inserted
+ * error will be thrown from the first call to {@link #read(byte[], int, int)} that attempts to read
+ * from the corresponding position, and from all subsequent calls to {@link #read(byte[], int, int)}
  * until the source is closed. If the source is closed and re-opened having encountered an error,
  * that error will not be thrown again.
+ *
+ * <p>Example usage:
+ *
+ * <pre>
+ *   // Create a FakeDataSource then add default data and two FakeData
+ *   // "test_file" throws an IOException when tried to be read until closed and reopened.
+ *   FakeDataSource fakeDataSource = new FakeDataSource();
+ *   fakeDataSource.getDataSet()
+ *       .newDefaultData()
+ *         .appendReadData(defaultData)
+ *         .endData()
+ *       .setData("http:///1", data1)
+ *       .newData("test_file")
+ *         .appendReadError(new IOException())
+ *         .appendReadData(data2);
+ *    // No need to call endData at the end
+ * </pre>
  */
 public final class FakeDataSource implements DataSource {
 
-  private final ArrayList<Segment> segments;
+  private final FakeDataSet fakeDataSet;
   private final ArrayList<DataSpec> openedDataSpecs;
 
-  private final boolean simulateUnknownLength;
-  private final long totalLength;
-
   private Uri uri;
   private boolean opened;
+  private FakeData fakeData;
   private int currentSegmentIndex;
   private long bytesRemaining;
 
-  private FakeDataSource(boolean simulateUnknownLength, ArrayList<Segment> segments) {
-    this.simulateUnknownLength = simulateUnknownLength;
-    this.segments = segments;
-    long totalLength = 0;
-    for (Segment segment : segments) {
-      totalLength += segment.length;
-    }
-    this.totalLength = totalLength;
-    openedDataSpecs = new ArrayList<>();
+  public static Factory newFactory(final FakeDataSet fakeDataSet) {
+    return new Factory() {
+      @Override
+      public DataSource createDataSource() {
+        return new FakeDataSource(fakeDataSet);
+      }
+    };
+  }
+
+  public FakeDataSource() {
+    this(new FakeDataSet());
+  }
+
+  public FakeDataSource(FakeDataSet fakeDataSet) {
+    this.fakeDataSet = fakeDataSet;
+    this.openedDataSpecs = new ArrayList<>();
+  }
+
+  public FakeDataSet getDataSet() {
+    return fakeDataSet;
   }
 
   @Override
@@ -69,6 +105,21 @@ public final class FakeDataSource implements DataSource {
     opened = true;
     uri = dataSpec.uri;
     openedDataSpecs.add(dataSpec);
+
+    fakeData = fakeDataSet.getData(uri.toString());
+    if (fakeData == null) {
+      throw new IOException("Data not found: " + dataSpec.uri);
+    }
+
+    long totalLength = 0;
+    for (Segment segment : fakeData.segments) {
+      totalLength += segment.length;
+    }
+
+    if (totalLength == 0) {
+      throw new IOException("Data is empty: " + dataSpec.uri);
+    }
+
     // If the source knows that the request is unsatisfiable then fail.
     if (dataSpec.position >= totalLength || (dataSpec.length != C.LENGTH_UNSET
         && (dataSpec.position + dataSpec.length > totalLength))) {
@@ -78,7 +129,7 @@ public final class FakeDataSource implements DataSource {
     boolean findingCurrentSegmentIndex = true;
     currentSegmentIndex = 0;
     int scannedLength = 0;
-    for (Segment segment : segments) {
+    for (Segment segment : fakeData.segments) {
       segment.bytesRead =
           (int) Math.min(Math.max(0, dataSpec.position - scannedLength), segment.length);
       scannedLength += segment.length;
@@ -91,7 +142,7 @@ public final class FakeDataSource implements DataSource {
     // Configure bytesRemaining, and return.
     if (dataSpec.length == C.LENGTH_UNSET) {
       bytesRemaining = totalLength - dataSpec.position;
-      return simulateUnknownLength ? C.LENGTH_UNSET : bytesRemaining;
+      return fakeData.simulateUnknownLength ? C.LENGTH_UNSET : bytesRemaining;
     } else {
       bytesRemaining = dataSpec.length;
       return bytesRemaining;
@@ -102,10 +153,10 @@ public final class FakeDataSource implements DataSource {
   public int read(byte[] buffer, int offset, int readLength) throws IOException {
     Assertions.checkState(opened);
     while (true) {
-      if (currentSegmentIndex == segments.size() || bytesRemaining == 0) {
+      if (currentSegmentIndex == fakeData.segments.size() || bytesRemaining == 0) {
         return C.RESULT_END_OF_INPUT;
       }
-      Segment current = segments.get(currentSegmentIndex);
+      Segment current = fakeData.segments.get(currentSegmentIndex);
       if (current.isErrorSegment()) {
         if (!current.exceptionCleared) {
           current.exceptionThrown = true;
@@ -140,12 +191,13 @@ public final class FakeDataSource implements DataSource {
     Assertions.checkState(opened);
     opened = false;
     uri = null;
-    if (currentSegmentIndex < segments.size()) {
-      Segment current = segments.get(currentSegmentIndex);
+    if (currentSegmentIndex < fakeData.segments.size()) {
+      Segment current = fakeData.segments.get(currentSegmentIndex);
       if (current.isErrorSegment() && current.exceptionThrown) {
         current.exceptionCleared = true;
       }
     }
+    fakeData = null;
   }
 
   /**
@@ -181,16 +233,21 @@ public final class FakeDataSource implements DataSource {
 
   }
 
-  /**
-   * Builder of {@link FakeDataSource} instances.
-   */
-  public static final class Builder {
+  /** Container of fake data to be served by a {@link FakeDataSource}. */
+  public static final class FakeData {
 
     private final ArrayList<Segment> segments;
+    private final FakeDataSet dataSet;
     private boolean simulateUnknownLength;
 
-    public Builder() {
-      segments = new ArrayList<>();
+    public FakeData(FakeDataSet dataSet) {
+      this.segments = new ArrayList<>();
+      this.dataSet = dataSet;
+    }
+
+    /** Returns the {@link FakeDataSet} this FakeData belongs to. */
+    public FakeDataSet endData() {
+      return dataSet;
     }
 
     /**
@@ -199,7 +256,7 @@ public final class FakeDataSource implements DataSource {
      * the {@link DataSpec#length} of the argument, including the case where the length is equal to
      * {@link C#LENGTH_UNSET}.
      */
-    public Builder setSimulateUnknownLength(boolean simulateUnknownLength) {
+    public FakeData setSimulateUnknownLength(boolean simulateUnknownLength) {
       this.simulateUnknownLength = simulateUnknownLength;
       return this;
     }
@@ -207,7 +264,7 @@ public final class FakeDataSource implements DataSource {
     /**
      * Appends to the underlying data.
      */
-    public Builder appendReadData(byte[] data) {
+    public FakeData appendReadData(byte[] data) {
       Assertions.checkState(data != null && data.length > 0);
       segments.add(new Segment(data, null));
       return this;
@@ -216,13 +273,41 @@ public final class FakeDataSource implements DataSource {
     /**
      * Appends an error in the underlying data.
      */
-    public Builder appendReadError(IOException exception) {
+    public FakeData appendReadError(IOException exception) {
       segments.add(new Segment(null, exception));
       return this;
     }
+  }
+
+  /** A set of {@link FakeData} instances. */
+  public static final class FakeDataSet {
+
+    private FakeData defaultData;
+    private final HashMap<String, FakeData> dataMap;
+
+    public FakeDataSet() {
+      dataMap = new HashMap<>();
+    }
+
+    public FakeData newDefaultData() {
+      defaultData = new FakeData(this);
+      return defaultData;
+    }
+
+    public FakeData newData(String uri) {
+      FakeData data = new FakeData(this);
+      dataMap.put(uri, data);
+      return data;
+    }
+
+    public FakeDataSet setData(String uri, byte[] data) {
+      newData(uri).appendReadData(data);
+      return this;
+    }
 
-    public FakeDataSource build() {
-      return new FakeDataSource(simulateUnknownLength, segments);
+    public FakeData getData(String uri) {
+      FakeData data = dataMap.get(uri);
+      return data != null ? data : defaultData;
     }
 
   }