@GwtIncompatible("java.util.regex.Pattern")
  public void containsMatch(@Nullable Pattern regex) {
    checkNotNull(regex);
    if (actual == null) {
      failWithActual("expected a string that contains a match for", regex);
    } else if (!regex.matcher(actual).find()) {
      failWithActual("expected to contain a match for", regex);
    }
  }
@Test
  public void stringContainsMatchStringFailNull() {
    expectFailureWhenTestingThat(null).containsMatch(".*b.*");
    assertFailureValue("expected a string that contains a match for", ".*b.*");
  }