Unit testing Javascript applications with qunit and sinon
Training goals
- Introduction to the tools (QUnit, Sinon)
- Overview of the test runner (Karma)
- How we integrate testing into a build
Qunit
TDD style testing framework that groups tests into modules and uses assertions to pass/fail tests.
QUnit running in the browser.
Assertion Types
| Truthiness | |
assert.ok(value)
|
Boolean(value) === true
|
assert.notOk(value)
|
Boolean(value) === false
|
| Equality | |
assert.equal(value1, value2)
|
value1 == value2
|
assert.strictEqual(value1, value2)
|
value1 === value2
|
assert.notEqual(value1, value2)
|
value1 != value2
|
assert.notStrictEqual(value1, value2)
|
value1 !== value2
|
assert.deepEqual(value1, value2)
|
angular.equals(value1, value2)*
|
Assertion Types (continued)
| Equality | |
assert.notDeepEqual(value1, value2)
|
!angular.equals(value1, value2)*
|
| Exceptions | |
assert.throws(func, Error)
|
function func() { throw new Error; }
|
sinon.js
Test spies, stubs, and additional assertions for dependencies used within your test.
sinon spies
- When you want to inspect the inputs and return values of a function.
- Validating your call stack
- Keep them within the object / class under test
sinon stubs
- When you want to inspect the inputs and return values of a function with predetermined behaviors.
- Use for calls out to dependencies
- Resources
- Services
- Really anything that is not the object / class under test.
sinon matchers
- Indicate a level of specificity for matching values
- Fuzzy or strict matching
- Good for matching objects
- Good for matching types like Array, RegExp, and Object
- Good for testing truthy / falsy values
Karma
A pluggable, framework-agnostic test runner with support for multiple browsers and devices.
Karma monitoring multiple browsers.
final thoughts
- Writing good tests is like writing good code - it takes practice and patterns
- 100% coverage is NOT the goal
- Stability is the goal
- Tests help to define your interface
