@Test
public void shouldThrowExceptionIfInputHasNoDefault() {

  var parameterMap = Interface.ParameterMap.newBuilder()
      .putParameters(KEY, Interface.Parameter.newBuilder()
          .setVar(Interface.Variable.newBuilder()
              .setType(Types.LiteralType.newBuilder().
                  setSimple(Types.SimpleType.STRING)
                  .build())
              .build())
          .build())
      .build();
  var exception = assertThrows(
      UnsupportedOperationException.class,
      () -> fillParameterInInputs(parameterMap, PARAMETER)
  );
  assertThat(exception.getMessage(), equalTo(EXCEPTION_MESSAGE));
}