Unsuccessful JASMINE unit test scenario

Question

Unsuccessful JASMINE unit test scenario

Having trouble with my function and spec test, as it is failing with the error:

Unhandled promise rejection: [object Object]

Function:

someFunction(a,b,c) {
    var dfd = q.defer();
    this.getInfo(b,c).then((data)=> {
       //do Something
    
      dfd.resolve(data);
    }).catch((error)=> {
       dfd.reject(error)
    })
    
    return dfd.promise;
}

Spec Test:

describe( 'SomeFunction', () => {
    it( 'should reject when getInfo request fails',  ( done ) => {
        spyOn( utility, 'getInfo' ).and.callFake( async () => {
            var deferred = q.defer();               
            deferred.reject( { error: 500 } );
            return deferred.promise;
        });
        let promise =  utility.someFunction( a,b,c );
        expect(utility.getInfo).toHaveBeenCalled();
        promise.then().catch( function ( data:any) {
            expect( data ).toEqual( { error: 500 } );
        } ).finally( done );
    });

I'm trying to write a test case for reject but keep getting an unhandled promise rejection error. If anyone could help, I'd appreciate it.

javascript typescript unit-testing jasmine karma-jasmine

Answer 1

Answer №1

To reject with a specific value, you can use the rejectWith(value) method:

This command instructs the spy to return a promise that rejects with the given value upon invocation.

This is particularly useful when spying on the utility.getInfo() method. Since the result of utility.someFunction is a promise, it is recommended to use expectAsync(actual) for creating asynchronous expectations.

The code in index.ts looks as follows:

import q from 'q';

const utility = {
  someFunction(a, b, c) {
    var dfd = q.defer();
    this.getInfo(b, c)
      .then((data) => {
        dfd.resolve(data);
      })
      .catch((error) => {
        dfd.reject(error);
      });
    return dfd.promise;
  },
  async getInfo(b, c) {
    return 'real data';
  },
};

export { utility };

In the test file index.test.ts:

import { utility } from './';

describe('69378465', () => {
  it('should pass', async () => {
    spyOn(utility, 'getInfo').and.rejectWith({ error: 500 });
    await expectAsync(utility.someFunction('a', 'b', 'c')).toBeRejectedWith({ error: 500 });
    expect(utility.getInfo).toHaveBeenCalled();
  });
});

After running the test, the output will be as follows:

Test Suites & Specs:

1. 69378465
   ✔ should pass (11ms)

>> Done!


Summary:

👊  Passed
Suites:  1 of 1
Specs:   1 of 1
Expects: 2 (0 failures)
Finished in 0.017 seconds

Answer 2

To reject with a specific value, you can use the rejectWith(value) method:

This command instructs the spy to return a promise that rejects with the given value upon invocation.

This is particularly useful when spying on the utility.getInfo() method. Since the result of utility.someFunction is a promise, it is recommended to use expectAsync(actual) for creating asynchronous expectations.

The code in index.ts looks as follows:

import q from 'q';

const utility = {
  someFunction(a, b, c) {
    var dfd = q.defer();
    this.getInfo(b, c)
      .then((data) => {
        dfd.resolve(data);
      })
      .catch((error) => {
        dfd.reject(error);
      });
    return dfd.promise;
  },
  async getInfo(b, c) {
    return 'real data';
  },
};

export { utility };

In the test file index.test.ts:

import { utility } from './';

describe('69378465', () => {
  it('should pass', async () => {
    spyOn(utility, 'getInfo').and.rejectWith({ error: 500 });
    await expectAsync(utility.someFunction('a', 'b', 'c')).toBeRejectedWith({ error: 500 });
    expect(utility.getInfo).toHaveBeenCalled();
  });
});

After running the test, the output will be as follows:

Test Suites & Specs:

1. 69378465
   ✔ should pass (11ms)

>> Done!


Summary:

👊  Passed
Suites:  1 of 1
Specs:   1 of 1
Expects: 2 (0 failures)
Finished in 0.017 seconds

Unsuccessful JASMINE unit test scenario

Answer №1

Similar questions

How to iterate through an array of objects in Javascript and extract an array of strings

React does not recognize the event.which property as undefined

Notifying the chosen option using jQuery

Tips on sending error messages to an MVC view during an Ajax call

Unlocking the potential of the Route component within the children of the useRoutes hook

Guide to building a React project with an outdated edition of Create React App

Change the :target in javascript

Include a legal disclaimer on a website comprised of individual pages

What is the best way to create an onwheel event that produces an up and down effect using JavaScript?

Using AJAX and jQuery, the result is retrieved and inserted into a <div> element

A function that can handle either a generic data type or an array containing elements of the same data type

Exploring the capabilities of mongoose and typescript led to encountering an error: RangeError - node_modules/mongodb/src/bson.ts:38:3 due to exceeding the maximum

Ways to execute a function when clicking on a date using HTML 5 datepicker input type

Events bound to JSX elements created in an array map are not being triggered by React

Incorporating traditional Javascript classes for modeling in React development

Managing bidirectional binding in Angular to optimize rendering performance

Compare the precise value of $(window).height() to a specific scroll value

What is the best way to utilize my function across several different elements?

When using ng-repeat with Angular ui-bootstrap and tabs, the new tab will not be selected if there are no existing tabs present

AngularJS showing up as normal text