Jasmine test

Very good introduction to Jasmine https://codecraft.tv/courses/angular/unit-testing/jasmine-and-karma

Video explanation : talk about unit test, what is it, test in general... The jasmine Documentation https://jasmine.github.io/api/3.0/global.html#beforeEach

JASMINE before / after functions

Run before all test suite tests

  • beforeAll

  • afterAll

Run before each test, before this test or after this test

  • beforeEach

  • afterEach

Disable temporarily a test

Put x in front of describe (the test suite = group of tests) xdesribe and x in front of it (the test) so xit

It allows to disable a test temporarily though still listing it and not commenting it To be able to see the test code.

Put f in front of it to focus only on one test (only run one test) so write fit('the test to focus on')

The hierarchy of unit test

  • A test suite : a group of test (describe)

  • A test spec : one individual test (it)

  • A test expectation : what we are testing (expect)

What do Karma do

Karma is a test runner, it is not compulsory to use it. Though it is easier :

  • It reruns the tests when code change

  • It open a separate browser (headless)

  • It gets Jasmine result in the command line


Jasmine Spy

Remove code duplication in Jasmine

https://juristr.com/blog/2014/10/avoid-test-code-duplication-jasmine Duplication using a way to invoke describe by using a function

https://gist.github.com/traviskaufman/11131303 Git that explain why using this in the test context. Some recent comment explained how to use it with typescript as well.

https://www.reddit.com/r/javascript/comments/60a10r/improve_your_javascript_unit_testing_with/ Discussion about how to write units tests with multiple expect in it or not, parameterized tests...

https://gist.github.com/sinsunsan/cb1779b3b83a33fe8446bf27ef7f6149 Example of parameterized test in JavaScript

Debug Jasmine test

  • Error due to a missing selector with debugElement

const myElement = fixture.debugElement.query(By.css(.missing-class));
// myElement.nativeElement will trigger an error

Failed: Uncaught (in promise): TypeError: Cannot read property 'nativeElement' of undefined

  • angular test with data that come from a resolver