Unit Testing in AngularJS
Unit testing is taking a solitary utmost or part of our code, and making affirmations and tests to guarantee that it fills in as organized. While phenomenally conventional on the server side, we regularly discover the tendency for making unit tests not right when making clientside applications. Here are five reasons why we should make unit tests when working on a JavaScript-based customer side application: Check of accuracy Without unit tests, there is apparently obstructed dependence on completely manual tests to guarantee that our segment or part of the application genuinely works. Unit tests go about as confirmation that what we have grown genuinely does what it should, that we have managed all the edge cases enough, and that it passes on the benefit understand these cases. Nonappearance of compiler In JavaScript, there isn't the scarcest piece like the Java compiler to reveal to us that something doesn't work. It is dependent upon the program to at long last reveal to us that something is broken, and even by at that point, various ventures produce various outcomes. Unit tests can be run a long time previously our application makes it out to the program to get issues and alarm us about our suppositions.
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| Angular JS |
Catch errors early:
Without unit tests, we would only know about an error in our application after we hit refresh in our browser and saw the live application. Unit tests can help us catch errors much earlier, reducing turnaround time and thus increasing our development speed.
Prevent regressions:
At the end of the day, we are unlikely to be the only person working on our codebase.Other developers will inevitably rely on or actively change parts of the codebase that we developed.You can ensure that they don’t change any fundamental assumptions by providing a set of unit tests that prevent regressions and bugs in the future.
Specification:
Comments have a bad habit
of becoming outdated. Unit tests in AngularJS, especially written using
Jasmine, look and read like English. And because unit tests break when the
underlying code changes, we are forced to keep comments updated. So unit tests
can act as a living, breathing specification for our codebase.
Introduction to Karma
Karma is
the test runner that makes running tests painless and amazingly fast. It uses NodeJS and SocketIO to facilitate tests in
multiple browsers at insanely fast speeds
Explaining the Karma Config:
To use Karma, we need a configuration file that tells Karma how to operate. We will see how easy it is to generate this configuration file in the next section. But first, let’s take a look at the Karma configuration and the options that we will use for our unit tests in this chapter. The default name for this file is karma.conf.js, and unless you tell Karma otherwise, it will automatically look for a file with this name in the directory you run
Karma from:
// File: chapter3/karma.conf.js
// Karma configuration
module.exports = function(config) {
config.set({
// base path that will be used to resolve files and exclude
basePath: '',
// testing framework to use (jasmine/mocha/qunit/...)
frameworks: ['jasmine'],
// list of files / patterns to load in the browser
files: [
'angular.min.js',
'angular-mocks.js',
'controller.js',
'simpleSpec.js',
'controllerSpec.js'
],
// list of files / patterns to exclude
exclude: [],
// web server port
Jasmine: Spec Style of Testing
In the previous section, we saw the test runner that we will use to run the unit tests we write for AngularJS. But the actual testing framework that we will use for the purpose of this book is Jasmine. The Jasmine framework uses what we call a behavior-driven style of writing tests.That is, instead of writing a bunch of functions and asserts, we describe behaviors and set expectations. How does this translate into actual tests? Let’s take a deeper look.
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| Jasmine Syntax |
Jasmine Syntax
Before we jump down into Jasmine syntax and talk about the various concepts of a Jasmine test, let’s take an example to make things clearer:
// A test suite in Jasmine
describe('My Function', function() {
var t;
// Similar to setup
beforeEach(function() {
t = true;
});
afterEach(function() {
t = null;
});
it('should perform action 1', function() {
expect(t).toBeTruthy();
});
it('should perform action 2', function() {
var expectedValue = true;
expect(t).toEqual(expectedValue);
});
});
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