@Test
public void testIsOnlyUpperCase() {

    assertTrue("'M' is uppercase only", ConversionHelper.isOnlyUpperCase("M"));
    assertTrue("'MOO' is uppercase only", ConversionHelper.isOnlyUpperCase("MOO"));
    assertFalse("'Moo' is NOT uppercase only", ConversionHelper.isOnlyUpperCase("Moo"));
    assertFalse("<null> is NOT uppercase only", ConversionHelper.isOnlyUpperCase(null));
}