IllegalArgumentException expected =
        assertThrows(IllegalArgumentException.class, () -> checkArgument(false, new Message()));
    verifySimpleMessage(expected);
  }

  public void testCheckArgument_nullMessage_failure() {
    IllegalArgumentException expected =
        assertThrows(IllegalArgumentException.class, () -> checkArgument(false, null));
    assertThat(expected).hasMessageThat().isEqualTo("null");
  }