FlexMock 0.5.0 Released¶ ↑
FlexMock is a flexible mocking library for use in Ruby's Test::Unit test framework. Version 0.5.0 adds the ability to automatically stub any instance created by an existing class.
New in 0.5.0¶ ↑
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flexstub(obj) will now accept a block argument in the same way that flexmock() does.
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When stubbing Class objects, the any_instance method can be used to automatically stub any instance object created by the class. For example, if you wish that any Connection object created during a test has a stubbed “send” method, you could do the following:
def test_connections flexstub(Connection).any_instance do |new_con| new_con.should_receive(:send).and_return(0) end connection = Connection.new connection.send # This calls the stubbed version of send. end
Only objects created during the test will be automatically stubbed.
Existing objects are unaffected.
What is FlexMock?¶ ↑
FlexMock is a flexible Ruby mocking library that works with Ruby's Test::Unit framework to create easy to use mocks.
Features¶ ↑
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Easy integration with Test::Unit. Mocks created with the flexmock method are automatically verified at the end of the test.
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A fluent interface that allows mock behavior to be specified very easily.
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A “record mode” where an existing implementation can record its interaction with a mock for later validation against a new implementation.
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Easy mocking of individual methods in existing, non-mock objects.
Example¶ ↑
Suppose you had a Dog object that wagged a tail when it was happy. Something like this:
class Dog def initialize(a_tail) @tail = a_tail end def happy @tail.wag end end
To test the Dog
class without a real Tail
object
(perhaps because real Tail
objects activate servos in some
robotic equipment), you can do something like this:
require 'test/unit' require 'flexmock'
class TestDog < Test::Unit::TestCase include FlexMock::TestCase def test_dog_wags_tail_when_happy tail = flexmock("tail") tail.should_receive(:wag).once dog = Dog.new(tail) dog.happy end end
FlexMock will automatically verify that
the mocked tail object received the message wag
exactly one
time. If it doesn't, the test will not pass.
See the FlexMock documentation at onestepback.org/software/flexmock for details on specifying arguments and return values on mocked methods, as well as a simple technique for mocking tail objects when the Dog class creates the tail objects directly.
Availability¶ ↑
You can make sure you have the latest version with a quick RubyGems command:
gem install flexmock (you may need root/admin privileges)
Otherwise, you can get it from the more traditional places:
You will find documentation at: onestepback.org/software/flexmock/
– Jim Weirich