Exploring the functionality of CanDeactiveGuard and ModalDialogService through unit testing

Question

Exploring the functionality of CanDeactiveGuard and ModalDialogService through unit testing

In my application, the CanDeactiveGuard is functioning properly. During unit testing, I encountered an issue with one test where I intended to use callThrough to invoke the openConfirmDialog() method within the Guard. This method triggers the Modal Dialog component that prompts the user to save changes. Although the method resides in the Guard, it actually calls a service to open the modal. My question is whether it is appropriate to execute the code in the ModalDialogService from a Guard method, or if I should test the service independently.

The Guard class and the ModalDialogService are the two key components involved in this scenario. Should the code within the ModalDialogService be executed from the Guard, or should it be tested separately?

Here's a snippet from the guard spec file:

(...mockGuardComponent and service tests...)

During the second test, I'm attempting to trigger the openConfirmDialog() method to launch the modal.

Below is an excerpt from the ModalDialogService class:

(...ModalDialogService class code...)

Given that the openConfirmDialog() method does not execute the code in the ModalDialogService, it seems necessary to test that functionality separately. Does this mean that I have to mock objects such as OverlayRef, ModalDialogConfig, and ModalDialogRef to create a dialog?

angular typescript

Answer 1

Answer №1

From my perspective :- It is essential to create a test case for ModalDialogService when conducting unit testing. Each file should have its test file along with corresponding test cases.

Regarding the test case below, ensure that the ModalDialogService is included in the provider section. Make sure to import the mock of the service (similar to this: providers:[{ provide:ModalDialogService , useValue: {yourMockvalues related to service} }]).

dialogService = TestBed.get(ModalDialogService);

// Note that using a spy will not necessarily trigger the service function, it must also be used in the expect statement.

When you use a spy on a method, the actual method is not invoked.

 it('cannot route if guarded -- form is dirty', () => {
// *** Here is where I'm trying to execute the openConfirmDialog() 
method that creates a modal
    spyOn(service, 'openConfirmDialog').and.callThrough(); // will not hit the actual method
    mockGuardComponent.returnValue = false;
    expect(service.canDeactivate(mockGuardComponent)).toBeFalsy();
    expect(service.openConfirmDialog).toHaveBeenCalled(); // you need to spy in order to inspect
  });

This test signifies that 'openConfirmDialog' will be triggered upon deactivation. Another test case should be created to determine the functionality of 'openConfirmDialog' itself.

Only mock the methods/properties utilized by the component.

For example, while ModalDialogService may have 5 methods, only 2 are utilized in PendingChangesGuard. Therefore, in PendingChangesGuard, only 2 methods of ModalDialogService should be mocked.

providers:[{ provide:ModalDialogService , useValue: {open: jasmine.createSpy('open')} }]

Answer 2

From my perspective :- It is essential to create a test case for ModalDialogService when conducting unit testing. Each file should have its test file along with corresponding test cases.

Regarding the test case below, ensure that the ModalDialogService is included in the provider section. Make sure to import the mock of the service (similar to this: providers:[{ provide:ModalDialogService , useValue: {yourMockvalues related to service} }]).

dialogService = TestBed.get(ModalDialogService);

// Note that using a spy will not necessarily trigger the service function, it must also be used in the expect statement.

When you use a spy on a method, the actual method is not invoked.

 it('cannot route if guarded -- form is dirty', () => {
// *** Here is where I'm trying to execute the openConfirmDialog() 
method that creates a modal
    spyOn(service, 'openConfirmDialog').and.callThrough(); // will not hit the actual method
    mockGuardComponent.returnValue = false;
    expect(service.canDeactivate(mockGuardComponent)).toBeFalsy();
    expect(service.openConfirmDialog).toHaveBeenCalled(); // you need to spy in order to inspect
  });

This test signifies that 'openConfirmDialog' will be triggered upon deactivation. Another test case should be created to determine the functionality of 'openConfirmDialog' itself.

Only mock the methods/properties utilized by the component.

For example, while ModalDialogService may have 5 methods, only 2 are utilized in PendingChangesGuard. Therefore, in PendingChangesGuard, only 2 methods of ModalDialogService should be mocked.

providers:[{ provide:ModalDialogService , useValue: {open: jasmine.createSpy('open')} }]

Answer 3

Answer №2

After some consideration, I have concluded that it would be more effective to test the service in its own specific file. To do this, I have crafted a straightforward unit test using the following code snippet:

it('should trigger a modal dialog', () => {
    spyOn(modalDialogService, 'open').and.callThrough();
    modalDialogService.open(ModalDialogComponent, null);
    expect(modalDialogService.open).toHaveBeenCalled();
  });

Surprisingly, I didn't have to simulate any dependencies of the ModalDialogService. All that was necessary was to input the ModalDialogComponent into the open method to initiate the testing of the code.

Answer 4

After some consideration, I have concluded that it would be more effective to test the service in its own specific file. To do this, I have crafted a straightforward unit test using the following code snippet:

it('should trigger a modal dialog', () => {
    spyOn(modalDialogService, 'open').and.callThrough();
    modalDialogService.open(ModalDialogComponent, null);
    expect(modalDialogService.open).toHaveBeenCalled();
  });

Surprisingly, I didn't have to simulate any dependencies of the ModalDialogService. All that was necessary was to input the ModalDialogComponent into the open method to initiate the testing of the code.

Exploring the functionality of CanDeactiveGuard and ModalDialogService through unit testing

Answer №1

Answer №2

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