Angularjs unit testing interview questions

Unit testing is a type of software testing where we test individual components of an application. In AngularJS Unit testing is performed using Jasmine and Karma. Jasmine is the testing framework used for writing the test and Karma is used run tests. We can also use TestBed and async to make testing asynchronous code, components, directives or services easier.

Karma: Karma is a tool of running tests on browsers it lets us spawn browsers and run jasmine tests inside of them.

Jasmine: It is a testing framework for Javascript programming language that supports Behaviour Driven Development (BDD) software development practice.

After installing Node.js, we can install the Karma test runner by running npm install karma --save-dev command.

spec in Jasmine represents a test case inside the test suite. We can define spec by calling the global Jasmine function it, which, like describe takes a string and a function.

Example

describe("Suite Name", function() {
    it("test spec", function() {
        expect( expression ).toEqual(true);
    }); 
});

toBeArray(), toBeArrayOfBooleans(), toBeFalse(), toBeCalculable(), toBeOddNumber(), toBeEmptyObject(), any.after(date) are few built in matchers in Jasmine. For complete list of Jasmine Matchers please visit Github Jasmine Matchers List

A headless browser, a browser without any kind of graphical user interface (GUI) provides computerized control of a web page in an environment alike to popular web browsers but is performed through a command-line interface or managing network communication. They are especially useful for examining web pages as they can render and understand HTML the very way a browser would, including styling components such as page layout, color, font selection and execution of JavaScript and AJAX which are usually not possible when using other testing methods.