Hi I have a function which I would like to unit test. This is my function.

let docProcess: IDocProcess;

public onCalling(args) {
    if (this.docProcess.viewMode) {
      this.makeCalls(args);
    }
}

This IDocProcess is an interface:

export interface IDocProcess {
  viewMode: boolean;
  editMode: boolean;
  deleteMode: boolean;
}

I would like to unit test the above function. If I pass docProcess.viewMode as true, makeCalls(args) function should be called. If false, then the function must not be called.

The following is my Unit test code:

 beforeEach(async(() => {

    TestBed.configureTestingModule({
      imports: [RouterTestingModule],
      declarations: [CallsComponent],
      providers: [
        MockData
      ],
      schemas: [CUSTOM_ELEMENTS_SCHEMA]
    }).compileComponents();
  }));


  beforeEach(() => {
    fixture = TestBed.createComponent(CallsComponent);
    component = fixture.componentInstance;
  });


  it('should call makeCalls() only on View Mode', () => {
    
    component.docProcess.viewMode = true;
    fixture.detectChanges();
    component.onCalling(mockArgsData);    
    expect(component.makeCalls).toHaveBeenCalled();

But the test results get failed. Getting cannot read properties of undefined (reading:'viewMode').

Is this because the Testing module couldn't recognize the interface. A similar situation like this, I am also getting "Cannot set properties of undefined (setting: variable_name)"

Please help me in resolving this.

CodePudding user response：

I think you can try with component.docProcess = {viewMode = true}; because since the property is not initialized you need to create the object instead of trying to asign one property to undefined

CodePudding user response：

Angular generally throws such errors while testing to check if that variable exists or not. Mostly writing that code inside if(variable_name) {--code giving undefied variable_name error---}

resolves the issue , as we are checking in our ts code that variable_name is not undefined.