@Test
public void getSignature() {

    final List<PipelineFunction.ParameterDefinition> parameterDefinitions =
            underTest.getSignature().getParameterDefinitions();
    assertThat(parameterDefinitions).hasSize(3);
    assertThat(parameterDefinitions.get(0).getName()).isEqualTo("filterValue");
    assertThat(parameterDefinitions.get(0).getType()).isEqualTo(String.class);
    assertThat(parameterDefinitions.get(1).getName()).isEqualTo("rqlFunction");
    assertThat(parameterDefinitions.get(1).getType()).isEqualTo(String.class);
    assertThat(parameterDefinitions.get(2).getName()).isEqualTo("comparedValue");
    assertThat(parameterDefinitions.get(2).getType()).isEqualTo(String.class);
}