@Test
  public void testBusinessKeyConstant() {
    // given:
    String businessKey = "myBusinessKey";
    ExtensionElements extensionElements = addExtensionElements(caseTask);
    CamundaIn businessKeyElement = createElement(extensionElements, null, CamundaIn.class);
    businessKeyElement.setCamundaBusinessKey(businessKey);

    // when
    CmmnActivity activity = handler.handleElement(planItem, context);

    // then
    CaseTaskActivityBehavior behavior = (CaseTaskActivityBehavior) activity.getActivityBehavior();
    CallableElement callableElement = behavior.getCallableElement();

    ParameterValueProvider businessKeyValueProvider = callableElement.getBusinessKeyValueProvider();
    assertNotNull(businessKeyValueProvider);

    assertTrue(businessKeyValueProvider instanceof ConstantValueProvider);
    assertEquals(businessKey, businessKeyValueProvider.getValue(null));
  }