    @Test
    public void shouldAcceptCandidateKey() {

        String[] listKeyValid = {"test.dot", "test.double.dot", "test.test_underscore",
                "test.test_double_underscore", "test.test_double_underscore.dot",
                "test.dot_double_underscore", "test.test2"};
        String[] listKeyInvalid = {"test", "space not accepted", "double..dot"};
        for (String key : listKeyValid) {
            assertTrue("The key '" + key + "' should be accepted as a valid key",
                    I18Next.isI18NextKeyCandidate(key));
        }
        for (String key : listKeyInvalid) {
            assertFalse("The key '" + key + "' should not be accepted as a valid key",
                    I18Next.isI18NextKeyCandidate(key));
        }
    }