CODEWITHSUNDEEP
javascripttypescriptjasminepromiserxjs
Jerzy Gruszka
Jerzy Gruszka

Reputation: 1769

Smart way to execute function in test n times and check each result in jasmine anynchronous code

I have a spec file:

export class StaticClass() {
  public static doSomething(): Promise<any> {
    public static id = randomString(8); //makes a random from letters
   }
}

it('should execute n times', done => {

for (let i=0; i<20; i++) {
   console.log(i);
   StaticClass.doSomething(parameter).then((done) => {
     let id = StaticClass.id;
     console.log(id);
     expect(id).toBeSomething(); //not important here
     done();
   });
}

afterEach(()=> console.log('after each'));


});

Problem is that I get id which is always the same and the test passes immediately.

Output is:

0
1 
2
.. 
19
edbcjiia
edbcjiia
edbcjiia
..
19 times the same string
afterEach

I want to check something with the string generated by Static Helper class. Maybye use RxJs inteval somehow ?

Upvotes: 0

Views: 39

Answers (1)

Benjamin Gruenbaum
Benjamin Gruenbaum

Reputation: 276596

You're calling done in every then of the function (which executes multiple times). It doesn't make a lot of sense if you want to wait for all the actions. You're also overriding done with the then parameter which makes no sense;

Instead, you should wait for all the requests:

it('should execute n times', done => {

var p = Promise.resolve(); // create chain
for (let i=0; i<20; i++) {
   p  = p.then(() => { // only execute after the last one is done.
     return StaticClass.doSomething(parameter).then(() => {
       expect(StaticClass.id).toBeSomething(); //not important here
     });
  }); // then returns a new promise and waits for the internal promise
}

afterEach(()=> console.log('after each'));

Upvotes: 1

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