static String formatMetadataVarTemplate(String key) {
        return "${" + key + '}';
    }
@Test
    public void givenKey_whenFormatMetadataVarTemplate_thenReturnTheSameStringAsFormat() {
        assertThat(TbNodeUtils.formatMetadataVarTemplate("key"), is("${key}"));
        assertThat(TbNodeUtils.formatMetadataVarTemplate("key"), is(String.format(METADATA_VARIABLE_TEMPLATE, "key")));

        assertThat(TbNodeUtils.formatMetadataVarTemplate(""), is("${}"));
        assertThat(TbNodeUtils.formatMetadataVarTemplate(""), is(String.format(METADATA_VARIABLE_TEMPLATE, "")));

        assertThat(TbNodeUtils.formatMetadataVarTemplate(null), is("${null}"));
        assertThat(TbNodeUtils.formatMetadataVarTemplate(null), is(String.format(METADATA_VARIABLE_TEMPLATE, (String) null)));
    }