*
 * <p>Using {@link Comparator} avoids certain types of bugs, for example when you meant to write
 * {@code .compare(a.foo, b.foo)} but you actually wrote {@code .compare(a.foo, a.foo)} or {@code
 * .compare(a.foo, b.bar)}. {@code ComparisonChain} also has a potential performance problem that
 * {@code Comparator} doesn't: it evaluates all the parameters of all the {@code .compare} calls,

  private void assertContainsExpectedLines(String separator) throws IOException {
    String expected = expectedLines.isEmpty() ? "" : Joiner.on(separator).join(expectedLines);
    if (!lines.isEmpty()) {
      // if we wrote any lines in writeLines(), there will be a trailing newline
      expected += separator;
    }
    assertEquals(expected, factory.getSinkContents());
  }

  private void assertContainsExpectedLines(String separator) throws IOException {
    String expected = expectedLines.isEmpty() ? "" : Joiner.on(separator).join(expectedLines);
    if (!lines.isEmpty()) {
      // if we wrote any lines in writeLines(), there will be a trailing newline
      expected += separator;
    }
    assertEquals(expected, factory.getSinkContents());
  }