.build()
        }
        1 * implicitInput.getInput() >> '/foo/bar'
        1 * implicitInput.getOutput() >> 'abcdef012'
        1 * validator.isValid(cachePolicy, _) >> true
        1 * service.isUpToDate('/foo/bar', 'abcdef012') >> false
        1 * serviceRegistry.find(SomeService) >> service
        1 * service.withImplicitInputRecorder(_) >> service

        assertFalse(StringUtil.isNumber("０１２３４５６７８９"));
        assertFalse(StringUtil.isNumber(""));
        assertFalse(StringUtil.isNumber("01234abcdef"));
        assertFalse(StringUtil.isNumber("abcdef01234"));
    }

    /**
     *
     */
    @Test
    public void testIsEmpty() {
        assertTrue(StringUtil.isEmpty(null));
        assertTrue(StringUtil.isEmpty(""));