Angular Testing with Jasmine/

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Test Asynchronous Code

Test Asynchronous Code

Learn when to use async/await syntax to test asynchronous code.

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Asynchronous code runs as a callback function, for example, after a timeout or interval. The best way to run asynchronous code in modern JavaScript is using the async/await notation. Jasmine makes this easy to test. Look at the example below, where we await the result of the loadPosts method before making our expectations.

function loadPosts() {
    return new Promise(resolve => {
        setTimeout(() => {
            resolve([{
                id: 1,
                title: 'First post',
                content: 'This is my first post',
            }]);
        }, 2000);
    });
}

describe('Blog page tests', () => {
    it('Returns users created in past year', async () => {
        let posts;

        posts = await loadPosts();

        expect(posts.length).toEqual(1);
        expect(posts).toEqual([{
            id: 1,
            title: 'First post',
            content: 'This is my first post',
        }]);
    });
});
The async/await syntax

In this example, we have a loadPosts method defined ...