Posted by James Mead
Fri, 01 Sep 2006 14:07:00 GMT
I really must get round to writing some better documentation for Mocha, but in the meantime here’s a quickstart guide1.
Mocha adds a couple of new methods to all objects and classes – expects which sets up auto-verified expectations and stubs which stubs the method allowing any number of calls.
Both the expects and stubs methods actually return an expectation object. Relevant methods on an expectation are: at_least, at_least_once, never, raises, returns, times, with, yields which are hopefully fairly self-explanatory. If not there are some clues here
Mocking a class method
product = Product.new
Product.expects(:find).with(1).returns(product)
assert_equal product, Product.find(1)
product = Product.new
product.expects(:save).returns(true)
assert product.save
prices = [stub(:pence => 1000), stub(:pence => 2000)]
product = Product.new
product.stubs(:prices).returns(prices)
assert_equal [1000, 2000], product.prices.collect {|p| p.pence}
Product.any_instance.stubs(:name).returns('stubbed_name')
product = Product.new
assert_equal 'stubbed_name', product.name
object = mock()
object.expects(:expected_method).with(:p1, :p2).returns(:result)
assert_equal :result, object.expected_method(:p1, :p2)
object = stub(:method1 => :result1, :method2 => :result2)
assert_equal :result1, object.method1
assert_equal :result2, object.method2
1 I wrote these examples without checking them, so there may be some typos.
Tags class, instance, interception, mock, quickstart, rails, ruby, stub, testing, tutorial | 3 comments
Posted by James Mead
Thu, 31 Aug 2006 04:25:00 GMT
It’s great to see that Gluttonous has been playing with Mocha. Like many people, he’s found the ability to mock or stub class methods particularly useful – and this is one of the key differentiators between Mocha and other Ruby mocking libraries.
He’s been trying to improve the test coverage for Rails and submitted this patch where there is an interesting discussion1 about why he would prefer to use Mocha. Interestingly, there has also been some recent discussion on the RSpec mailing list about adding Mocha-like functionality.
On a different note, in his article Mocks for Speed, Gluttonous draws attention to one of the advantages I have previously mentioned of using mocks extensively to write unit tests that test a class in isolation – namely a fast build.
1 We have now released Mocha under the MIT license so it can be used for testing within Rails.
Tags class, fixture, instance, method, mock, mocking, rails, ruby, stub, stubbing, test, testing | 4 comments
Posted by James Mead
Sun, 16 Jul 2006 18:59:00 GMT
I thought I’d put the examples from the RDoc README up here if only for the syntax highlighting.
class Enterprise
def initialize(dilithium)
@dilithium = dilithium
end
def go(warp_factor)
warp_factor.times { @dilithium.nuke(:anti_matter) }
end
end
require 'rubygems'
require 'mocha'
require 'test/unit'
class EnterpriseTest < Test::Unit::TestCase
include Mocha
def test_should_boldly_go
dilithium = Mock.new
dilithium.expects(:nuke).with(:anti_matter).at_least_once
enterprise = Enterprise.new(dilithium)
enterprise.go(2)
dilithium.verify
end
end
Tags expectation, instance, method, mock, mocking, ruby, stub, stubbing, test, testing | no comments
