public static void checkValuesEqual(
      long value1,
      String value1Name,
      long value2,
      String value2Name) {
    checkArgument(
        value1 == value2,
        "'%s' (%s) must equal '%s' (%s).",
        value1Name,
        value1,
        value2Name,
        value2);
  }
@Test
  public void testCheckValuesEqual() throws Exception {
    // Should not throw.
    Validate.checkValuesEqual(1, "arg1", 1, "arg2");

    // Verify it throws.

    intercept(IllegalArgumentException.class,
        "'arg1' (1) must equal 'arg2' (2)",
        () -> Validate.checkValuesEqual(1, "arg1", 2, "arg2"));

  }