}

  public void testClosesOnErrors_whenWriteThrows() {
    TestCharSink failSink = new TestCharSink(WRITE_THROWS);
    assertThrows(IOException.class, () -> new TestCharSource(STRING).copyTo(failSink));
    assertTrue(failSink.wasStreamClosed());
  }

  public void testClosesOnErrors_whenWritingFromReaderThatThrows() {
    TestCharSink okSink = new TestCharSink();

  static final CharSource BROKEN_OPEN_SOURCE = new TestCharSource("ABC", OPEN_THROWS);
  static final CharSink BROKEN_WRITE_SINK = new TestCharSink(WRITE_THROWS);
  static final CharSink BROKEN_CLOSE_SINK = new TestCharSink(CLOSE_THROWS);
  static final CharSink BROKEN_OPEN_SINK = new TestCharSink(OPEN_THROWS);

  private static final ImmutableSet<CharSource> BROKEN_SOURCES =

  }

  public void testClosesOnErrors_whenWriteThrows() {
    TestCharSink failSink = new TestCharSink(WRITE_THROWS);
    assertThrows(IOException.class, () -> new TestCharSource(STRING).copyTo(failSink));
    assertTrue(failSink.wasStreamClosed());
  }

  public void testClosesOnErrors_whenWritingFromReaderThatThrows() {
    TestCharSink okSink = new TestCharSink();

    assertEquals(expected.length(), source.copyTo(builder));

    assertExpectedString(builder.toString());
  }

  public void testCopyTo_charSink() throws IOException {
    TestCharSink sink = new TestCharSink();

    assertEquals(expected.length(), source.copyTo(sink));

    assertExpectedString(sink.getString());
  }

  public void testRead_toString() throws IOException {