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Jasmine

  • Javascript unit testing
  • Influenced by RSpec
  • BDD style syntax
  • Supports headless out of box

Cheatsheet

Test suite

A group of related specs

Defined by calling describe, which takes two params;

  • name for spec suite (usually what is being tested)
  • function - one or more specs

Test suites can be nested too

Specs

Defined by calling it, which takes two params;

  • name of spec
  • function - one or more expectations that test the stae of code

Expectations

Build with expect, which takes a value, called the 'actual'

Chain with a Matcher function, which takes the expected value

Matchers

Implements a boolean comparison between the actual value and the expected value

This will report to Jasmine if the spec passed or failed

Can evaluate to negative by chaining expect with a not before the matcher

Included matchers

  • toBe
    • Compares with ===
  • toEqual
    • Compares with ==
  • toMatch
    • Regular expressions
  • toBeDefined
    • Compare against undefined
  • toBeUndefined
  • toBeNull
  • toBeTruthy
    • Boolean casting
  • toBeFalsy
  • toContain
    • Find item in array
  • toBeLessThan
  • toBeGreaterThan
  • toBeCloseTo
  • Precision match comparison
  • toThrow
    • Exception testing (any exception)
  • toThrowError
    • Accepts message, regular expression, or Exception object

Manual fail

Use fail method, which accepts an error message

Good for testing callbacks that should not be reached

Setup and teardown

Use these functions;

  • beforeEach
  • afterEach
  • beforeAll
  • afterAll
describe("A spec using beforeEach and afterEach", function() {
  this.foo = 0;

  beforeEach(function() {
    this.foo += 1;
  });

  afterEach(function() {
    this.foo = 0;
  });

  it("should call beforeEach", function() {
    expect(this.foo).toEqual(1);
  });
});

Disable / skip

Add an 'x' before describe or it functions

Spies

Stubs any function and tracks calls and arguments

spyOn(object, 'functionName');

Only exists within the describe or it in which its defined

Match

  • toHaveBeenCalled
  • toHaveBeenCalledWith(param1, param2)
    • True if argument list matches any of recorded calls
expect(object.functionName).toHaveBeenCalled();

Test with arguments;

expect(object.functionName).toHaveBeenCalledWith(param1, param2);

Will return true if any calls match

callThrough

Keep existing implementation

spyOn(object, 'functionName').and.callThrough();

returnValue

Force a simple response

spyOn(object, 'functionName').and.returnValue(123);

Or an implementation;

spyOn(object, 'functionName').and.returnValue(function() {
  return 123;
});

throwError

All calls to spy will throw value as error

spyOn(object, 'functionName').and.throwError('example');

@TODO

Up to here: http://jasmine.github.io/2.3/introduction.html#section-Spies:_and.throwError