}

  public void testReadFirstLine() throws IOException {
    TestCharSource lines = new TestCharSource(LINES);
    assertThat(lines.readFirstLine()).isEqualTo("foo");
    assertTrue(lines.wasStreamOpened() && lines.wasStreamClosed());
  }

  public void testReadLines_toList() throws IOException {
    TestCharSource lines = new TestCharSource(LINES);

  }

  public void testClosesOnErrors_copyingFromCharSourceThatThrows() {
    for (TestOption option : EnumSet.of(OPEN_THROWS, READ_THROWS, CLOSE_THROWS)) {
      TestCharSource failSource = new TestCharSource(STRING, option);
      TestCharSink okSink = new TestCharSink();
      assertThrows(IOException.class, () -> failSource.copyTo(okSink));

  }

  public void testClosesOnErrors_copyingFromCharSourceThatThrows() {
    for (TestOption option : EnumSet.of(OPEN_THROWS, READ_THROWS, CLOSE_THROWS)) {
      TestCharSource failSource = new TestCharSource(STRING, option);
      TestCharSink okSink = new TestCharSink();
      assertThrows(IOException.class, () -> failSource.copyTo(okSink));