Move FakeDataSet to seperate class.

This allows to create extensions of FakeDataSet and also simplifies the
FakeDataSource class.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=162180952

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

@@ -21,8 +21,8 @@ import android.net.Uri;
 import android.test.InstrumentationTestCase;
 import android.test.InstrumentationTestCase;
 import android.test.MoreAsserts;
 import android.test.MoreAsserts;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.testutil.FakeDataSet.FakeData;
 import com.google.android.exoplayer2.testutil.FakeDataSource;
 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.DataSpec;
 import com.google.android.exoplayer2.upstream.FileDataSource;
 import com.google.android.exoplayer2.upstream.FileDataSource;
 import com.google.android.exoplayer2.util.Util;
 import com.google.android.exoplayer2.util.Util;

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

@@ -21,8 +21,8 @@ import static com.google.android.exoplayer2.testutil.CacheAsserts.assertCachedDa
 import android.net.Uri;
 import android.net.Uri;
 import android.test.InstrumentationTestCase;
 import android.test.InstrumentationTestCase;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.testutil.FakeDataSet;
 import com.google.android.exoplayer2.testutil.FakeDataSource;
 import com.google.android.exoplayer2.testutil.FakeDataSource;
-import com.google.android.exoplayer2.testutil.FakeDataSource.FakeDataSet;
 import com.google.android.exoplayer2.testutil.TestUtil;
 import com.google.android.exoplayer2.testutil.TestUtil;
 import com.google.android.exoplayer2.upstream.DataSpec;
 import com.google.android.exoplayer2.upstream.DataSpec;
 import com.google.android.exoplayer2.upstream.cache.CacheUtil.CachingCounters;
 import com.google.android.exoplayer2.upstream.cache.CacheUtil.CachingCounters;

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

@@ -19,8 +19,7 @@ import static junit.framework.Assert.assertEquals;
 
 
 import android.net.Uri;
 import android.net.Uri;
 import android.test.MoreAsserts;
 import android.test.MoreAsserts;
-import com.google.android.exoplayer2.testutil.FakeDataSource.FakeData;
-import com.google.android.exoplayer2.testutil.FakeDataSource.FakeDataSet;
+import com.google.android.exoplayer2.testutil.FakeDataSet.FakeData;
 import com.google.android.exoplayer2.upstream.DataSourceInputStream;
 import com.google.android.exoplayer2.upstream.DataSourceInputStream;
 import com.google.android.exoplayer2.upstream.DataSpec;
 import com.google.android.exoplayer2.upstream.DataSpec;
 import com.google.android.exoplayer2.upstream.DummyDataSource;
 import com.google.android.exoplayer2.upstream.DummyDataSource;

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

+/*
+ * Copyright (C) 2017 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 com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.upstream.DataSpec;
+import com.google.android.exoplayer2.util.Assertions;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+
+/**
+ * Collection of {@link FakeData} to be served by a {@link FakeDataSource}.
+ *
+ * <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 FakeDataSource#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 FakeDataSource#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 FakeData#appendReadError(IOException)}. An inserted
+ * error will be thrown from the first call to {@link FakeDataSource#read(byte[], int, int)} that
+ * attempts to read from the corresponding position, and from all subsequent calls to
+ * {@link FakeDataSource#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>Actions are inserted by calling {@link FakeData#appendReadAction(Runnable)}. An actions is
+ * triggered when the reading reaches action's position. This can be used to make sure the code is
+ * in a certain state while testing.
+ *
+ * <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)
+ *         .endData();
+ * </pre>
+ */
+public final class FakeDataSet {
+
+  /** Container of fake data to be served by a {@link FakeDataSource}. */
+  public static final class FakeData {
+
+    /**
+     * A segment of {@link FakeData}. May consist of an action or exception instead of actual data.
+     */
+    public static final class Segment {
+
+      public final IOException exception;
+      public final byte[] data;
+      public final int length;
+      public final Runnable action;
+
+      public boolean exceptionThrown;
+      public boolean exceptionCleared;
+      public int bytesRead;
+
+      private Segment(byte[] data) {
+        this(data, data.length, null, null);
+      }
+
+      private Segment(int length) {
+        this(null, length, null, null);
+      }
+
+      private Segment(IOException exception) {
+        this(null, 0, exception, null);
+      }
+
+      private Segment(Runnable action) {
+        this(null, 0, null, action);
+      }
+
+      private Segment(byte[] data, int length, IOException exception, Runnable action) {
+        this.exception = exception;
+        this.action = action;
+        this.data = data;
+        this.length = length;
+      }
+
+      public boolean isErrorSegment() {
+        return exception != null;
+      }
+
+      public boolean isActionSegment() {
+        return action != null;
+      }
+
+    }
+
+    /** Uri of the data or null if this is the default FakeData. */
+    public final String uri;
+    private final ArrayList<Segment> segments;
+    private final FakeDataSet dataSet;
+    private boolean simulateUnknownLength;
+
+    private FakeData(FakeDataSet dataSet, String uri) {
+      this.uri = uri;
+      this.segments = new ArrayList<>();
+      this.dataSet = dataSet;
+    }
+
+    /** Returns the {@link FakeDataSet} this FakeData belongs to. */
+    public FakeDataSet endData() {
+      return dataSet;
+    }
+
+    /**
+     * When set, {@link FakeDataSource#open(DataSpec)} will behave as though the source is unable to
+     * determine the length of the underlying data. Hence the return value will always be equal to
+     * the {@link DataSpec#length} of the argument, including the case where the length is equal to
+     * {@link C#LENGTH_UNSET}.
+     */
+    public FakeData setSimulateUnknownLength(boolean simulateUnknownLength) {
+      this.simulateUnknownLength = simulateUnknownLength;
+      return this;
+    }
+
+    /**
+     * Appends to the underlying data.
+     */
+    public FakeData appendReadData(byte[] data) {
+      Assertions.checkState(data != null && data.length > 0);
+      segments.add(new Segment(data));
+      return this;
+    }
+
+    /**
+     * Appends data of the specified length. No actual data is available and this data should not
+     * be read.
+     */
+    public FakeData appendReadData(int length) {
+      Assertions.checkState(length > 0);
+      segments.add(new Segment(length));
+      return this;
+    }
+
+    /**
+     * Appends an error in the underlying data.
+     */
+    public FakeData appendReadError(IOException exception) {
+      segments.add(new Segment(exception));
+      return this;
+    }
+
+    /**
+     * Appends an action.
+     */
+    public FakeData appendReadAction(Runnable action) {
+      segments.add(new Segment(action));
+      return this;
+    }
+
+    /** Returns the whole data added by {@link #appendReadData(byte[])}. */
+    public byte[] getData() {
+      ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+      for (Segment segment : segments) {
+        if (segment.data != null) {
+          try {
+            outputStream.write(segment.data);
+          } catch (IOException e) {
+            throw new IllegalStateException(e);
+          }
+        }
+      }
+      return outputStream.toByteArray();
+    }
+
+    /** Returns the list of {@link Segment}s. */
+    public List<Segment> getSegments() {
+      return segments;
+    }
+
+    /** Retuns whether unknown length is simulated */
+    public boolean isSimulatingUnknownLength() {
+      return simulateUnknownLength;
+    }
+  }
+
+  private final HashMap<String, FakeData> dataMap;
+  private FakeData defaultData;
+
+  public FakeDataSet() {
+    dataMap = new HashMap<>();
+  }
+
+  /** Sets the default data, overwrites if there is one already. */
+  public FakeData newDefaultData() {
+    defaultData = new FakeData(this, null);
+    return defaultData;
+  }
+
+  /** Sets random data with the given {@code length} for the given {@code uri}. */
+  public FakeDataSet setRandomData(String uri, int length) {
+    return setData(uri, TestUtil.buildTestData(length));
+  }
+
+  /** Sets the given {@code data} for the given {@code uri}. */
+  public FakeDataSet setData(String uri, byte[] data) {
+    return newData(uri).appendReadData(data).endData();
+  }
+
+  /** Returns a new {@link FakeData} with the given {@code uri}. */
+  public FakeData newData(String uri) {
+    FakeData data = new FakeData(this, uri);
+    dataMap.put(uri, data);
+    return data;
+  }
+
+  /** Returns the data for the given {@code uri}, or {@code defaultData} if no data is set. */
+  public FakeData getData(String uri) {
+    FakeData data = dataMap.get(uri);
+    return data != null ? data : defaultData;
+  }
+
+  /** Returns a list of all data including {@code defaultData}. */
+  public ArrayList<FakeData> getAllData() {
+    ArrayList<FakeData> fakeDatas = new ArrayList<>(dataMap.values());
+    if (defaultData != null) {
+      fakeDatas.add(defaultData);
+    }
+    return fakeDatas;
+  }
+
+}