karma-jasmine - Row Coding

How do I unit test if an element is visible when the *ngIf directive is used using Jasmine in Angular

If the element is hidden, then it wont be rendered inside the dom. You can check expect(fixture.debugElement.query(By.css(‘.header’))).toBeUndefined(); EDIT : toBeNull() works better in the above case expect(fixture.debugElement.query(By.css(‘.header’))).toBeNull(); And also you have a syntax error while fetching the button element. nativeElement is not a function. Change it this way : const button = fixture.debugElement.query(By.css(‘button’)).nativeElement;

Karma – Chrome failed 2 times (cannot start). Giving up

by Tarik

I had the same problem and tried a lot of the suggested solutions I found, but what finally solved it for me was to delete the node_modules folder and getting everything new via npm install.

how to fix Error: ASSERTION ERROR: Should be run in update mode [Expected=> false == true

by Tarik

I got it all working, I have placed the function getVersionInfos in the ngOnInit instead of inside the constructor

How do I exclude files from karma code coverage report?

by Tarik

You can use several techniques here: karma uses minimatch globs for file paths and use can take advantage of that to exclude some paths. As first solution I’d say try to add only the paths of the file to preprocess with the coverage: // karma.conf.js module.exports = function(config) { config.set({ files: [ ‘src/**/*.js’, ‘test/**/*.js’ ], …

TypeError: undefined is not a constructor

by Tarik

undefined is not a constructor is an error message PhantomJS displays when you tried to call a function that is not defined. It depends on the version of ECMAScript which your PhantomJS supports. So as you said it works fine in Chrome, because this browser supports the function you are using in test. In order …

Testing ngOnChanges lifecycle hook in Angular 2

by Tarik

Guess I’m a little late to the party, However this may be useful to some one in the future. There have been a few changes to testing since RC 5 of angular has been released. However the main issue over here is ngOnChanges is not called when inputs are set programmatically. See this for more …

MatDialog Service Unit Test Angular 6 Error

by Tarik

Testing mat-dialogs can be tricky. I tend to use a spy object for the return from a dialog open (dialogRefSpyObj below) so I can more easily track and control tests. In your case it might look something like the following: describe(‘ModalService’, () => { let modalService: ModalService; let dialogSpy: jasmine.Spy; let dialogRefSpyObj = jasmine.createSpyObj({ afterClosed …

TypeError: Cannot read properties of undefined (reading ‘id’)

by Tarik

What is happening: The function itemToForm() is being called before the this.item is ready. There are many strategies to avoid this error. A very simple one is to add a catcher at the beginning of the function, like this: itemToForm = () => { if(this.item === undefined) {return} // The rest of the code } …

Expect not toThrow function with arguments – Jasmine

by Tarik

toThrow matcher requires function to be passed as argument to expect so you can simply wrap your function call in anonymous function: expect(function() { myFunc(arg1, arg2, arg3); }).not.toThrow(); You can also use bind to create new ‘version’ of your function that when called will be passed provided arguments: expect(myFunc.bind(null, arg1, arg2, arg3)).not.toThrow();

Angular 4 – Failed: Can’t resolve all parameters for ActivatedRoute: (?, ?, ?, ?, ?, ?, ?, ?)

by Tarik

You want to inject a fake ActivatedRoute to your component, since you create it yourself in the test, and the router thus doesn’t create it for you and inject an ActivatedRoute. So you can use something like this: describe(‘SomeComponent’, () => { const fakeActivatedRoute = { snapshot: { data: { … } } } as …