* it does.
   *
   * @throws IOException if an I/O error occurs while reading from this source
   */
  @CheckForNull
  public String readFirstLine() throws IOException {
    Closer closer = Closer.create();
    try {
      BufferedReader reader = closer.register(openBufferedStream());
      return reader.readLine();
    } catch (Throwable e) {

    assertTrue(source.wasStreamOpened() && source.wasStreamClosed());
  }

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

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