1. Quick Tour to Front-End Unit Testing Using
Jasmine
Gil Fink
Join the conversation on Twitter: @SoftArchConf #SA2014

2. Agenda
• Why Unit Testing?
• Behavior Driven Development
• Unit Testing in JavaScript?
• Jasmine
• Jasmine and Karma

3. Life Without Unit Testing

4. Why Unit Testing?
• Tests
– Act as safety net when you modify your code
• Increase your confidence in your code
– Encourage good design
– Help to detect bugs in early stages of the project
– Serve as live documentation

5. Behavior Driven Development
• Development approach based on test driven
development (TDD)
• Combines the good parts of different
development approaches
– Test driven development (TDD)
– Domain driven development (DDD)
– Object oriented analysis (OOA)
– Object oriented design (OOD)
– The combination of approaches isn’t mandatory

6. Behavior Driven Development –
Cont.
• BDD specifies that tests should be created for
the requirements (behaviors)
– Set by the business owners
• Developers and business owners should
collaborate to specify the requirements
• The output of the tests should be readable
– For to the developer
– For the business owners

7. BDD and TDD

8. BDD Language
• In BDD you
– describe your code
– tell the test what it (the code) should do
– expect your code to do something
//suite
describe ('', function(){
//test
it ('', function(){
//expectation
expect();
)};
});

9. Unit Testing in JavaScript?
• JavaScript is everywhere
– Browsers
– Servers
– Operation Systems
– Databases
– Mobile
– Devices
• You are doing it in any other language…

10. Jasmine
• JavaScript BDD framework
• Can be downloaded from:
http://jasmine.github.io/

11. Setting Up The Environment
• Download Jasmine
– or use a package manager such as Bower or Nuget
• Create a Spec (Test) Runner file
– Responsible to run all the unit tests
– Runs in the browser
• Create the Unit Test files
• Jasmine can also run headless
– Without a browser context

12. Demo
SETTING THE ENVIRONMENT

13. Suggested Folder Structure
js
|--src
|--tests
| |--spec
|--vendor
| |--jasmine
SpecRunner.html

14. Jasmine Tests Suites
• First create a Suite which is a Specs container
– Use the describe function
– Typically a single suite should be written for each
JavaScript file
describe("Suite Name", function() {
// Put here your tests
});

15. Jasmine Tests
• A Spec (Test) is defined by calling the it
function
– Receives a spec name and a spec callback function
– Contains expectations that test the state of the
code
de scribe("Suite Name", function() {
it("a spec with one expectation", function() {
// create the spec body
});
});

16. Expectations
• Expectations are assertions
– Can be either true or false
• Use the expect function within a spec to
declare an expectation
– Receives the actual value as parameter
• Include fluent API for matchers
– A Matcher is a comparison between the actual
and the expected values

17. Matchers Example
it("matchers", function() {
var a = 12,
b = a,
c = function () {
};
expect(a).toBe(b);
expect(a).not.toBe(null);
expect(a).toEqual(12);
expect(null).toBeNull();
expect(c).not.toThrow();
});

18. Demo
CREATING SUITES AND SPECS

19. More on Suites and Specs
• You can disable a test suite by using xdescribe
• You can mark a spec as pending (not running)
– Using xit
– By calling the pending function
xdescribe("A spec", function() {
xit(“that is pending", function() {
pending();
});
});

20. Creating a Custom Matcher
• You can create your own custom matcher
• The matcher should return true/false
according to the actual value and the
expectation you set

21. Setup and Teardown
• Jasmine includes
– beforeEach – runs before each test
– afterEach – runs after each test
• Should exists inside a test suite

22. Setup/Teardown Example
describe("A suite", function() {
var index = 0;
beforeEach(function() {
index += 1;
});
afterEach(function() {
index = 0;
});
it("a spec", function() {
expect(index).toEqual(1);
});
});

23. Demo
USING SETUP AND TEARDOWN

24. Nested describe Calls
• Calls for describe can be nested
– Good for creation of hierarchies
• The beforeEach/afterEach of nested describe
runs after a parent describe
describe("A spec", function() {
describe("nested inside a second describe", function() {
});
});

25. Working with Spies
• A spy is a test double object
• It replaces the real implementation and fake
its behavior
• Use spyOn, createSpy and createSpyObj
functions

26. Demo
WORKING WITH SPIES

27. Jasmine Async Support
• Jasmine enables to test async code
• Calls to beforeEach, it, and afterEach take an
additional done function
beforeEach(function(done) {
setTimeout(function() {
value = 0;
done();
}, 1);
});
// spec will not start until the done in beforeEach is called
it("should support async execution", function(done) {
value++;
expect(value).toBeGreaterThan(0);
done();
});

28. Demo
WORKING WITH ASYNC FUNCTIONS

29. Jasmine and Karma
• Karma is a test runner for JavaScript
– Executes JavaScript code in multiple browser
instances
– Makes BDD/TDD development easier
– Can use any JavaScript testing library
• In this session we will use Jasmine

30. Demo
JASMINE AND KARMA

31. Questions?

32. Summary
• Unit Tests are an important part of any
development process
• Jasmine library can help you to test your
JavaScript code
• Add tests to your JavaScript code!

33. Resources
• Session slide deck –
• Jasmine – http://jasmine.github.io/
• My Website – http://www.gilfink.net
• Follow me on Twitter – @gilfink

34. Thank You