public abstract String render(String inline) throws IllegalVariableEvaluationException;
@Test
    void withNullLabel() throws IllegalVariableEvaluationException {
        Flow flow = Flow.builder().id("triggerWithDefaultInput").namespace("io.kestra.test").revision(1).inputs(List.of(StringInput.builder().id("test").type(Type.STRING).defaults("test").build())).build();
        Execution execution = Execution.builder().id(IdUtils.create()).flowId("triggerWithDefaultInput").namespace("io.kestra.test").state(new State()).labels(List.of(new Label("key", null), new Label(null, "value"))).build();

        RunContext runContext = runContextFactory.of(flow, execution);

        assertThat(runContext.render("{{inputs.test}}"), is("test"));
    }