# \[ANN\] Mockery initial release (yet another dynamic mock object generator) **URL:** \ **Category:** ruby-talk\ **Created:** [19 August 2005 00:12 UTC](https://rubytalk.org/t/ann-mockery-initial-release-yet-another-dynamic-mock-object-generator/20266 "2005-08-19T00:12:08Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Gary\_Shea](https://avatars.discourse-cdn.com/v4/letter/g/779978/32.png) [@Gary\_Shea](https://rubytalk.org/u/Gary_Shea)\ **Post date:** [19 August 2005 00:12 UTC](https://rubytalk.org/t/ann-mockery-initial-release-yet-another-dynamic-mock-object-generator/20266/1 "2005-08-19T00:12:08Z")
Ruby is a really easy language to write mocks in, and it took thousands of lines of test-first code before I finally got tired of typing unit-test code like:   x\_class = Class.new(Some::Klass)   x\_class.class\_eval {     attr\_reader :blah     attr\_writer :ret\_val     def doit(blah)       @blah = blah       return @ret\_val     end   }   x = x\_class.new   ret\_val = Object.new   x.ret\_val = ret\_val   rv = x.please\_call\_doit(blah)   assert\_equal(blah, x.blah)   assert\_equal(ret\_val, rv) There's probably one of these mock objects for every 5-10 lines of my program code, and that adds up to a LOT of typing. Mockery ([http://rubyforge.org/projects/mockery](http://rubyforge.org/projects/mockery)) is a Ruby version of the kind of dynamic mock generator that is commonplace in Java. The Java versions tend to do a lousy job mocking classes as opposed to interfaces, but we don't have that problem in Ruby (not only are there no interfaces, but dynamic class modification is SO easy it's just not an issue). A first draft of the above example using Mockery looks like:   ctl = Mockery::Controller.new(Some::Klass)   ctl.record do |x|     x.doit('blah')   end   ctl.try do |x|     x.please\_call\_doit('blah')   end   assert\_equal(true, ctl.validate, ctl.error\_report) This code will detect if the call to #please\_call\_doit really calls #doit with the correct argument, exactly one time. #doit need not actually exist in Some::Klass -- because it's mentioned in the #record block, it will be mocked in the #try block. You may be thinking that the above test fails to handle the return value that the hand-coded example checks. Mockery can do that too. Each time a call is made to a recording object (arguments to the #record block), a call object is returned. The call object's #return\_value= method may be used to set a desired return value:   ctl = Mockery::Controller.new(Some::Klass)   ctl.record do |x|     call = x.doit(blah)     call.return\_value = 'blork'   end   ctl.try do |x|     rv = x.please\_call\_doit(blah)     assert\_equal('blork', rv)   end   assert\_equal(true, ctl.validate, ctl.error\_report) which fully captures the test done in the coded-by-hand version. The lines-of-code count is not vastly different, but the potential for error is, as is the amount of thought that goes into the test. I find working with Mockery much faster. Finally, an arbitrary number of classes to mock may be handed to the Mockery::Controller#new, each of which will be provided with a recorder argument in the #record block, and a mock in the #try block. This is a first release, so it's far short of perfect. I have tentative plans for a number of improvements, and I'm open to suggestions. I'm especially open to patches 🙂 The biggest weakness of Mockery at the moment is that it does not have a clue about mocking methods that use a block. Let me catch my breath before tackling that one 😉 Regards,   Gary Shea ---
**Author:** ![Pit](https://avatars.discourse-cdn.com/v4/letter/p/f14d63/32.png) [@Pit](https://rubytalk.org/u/Pit)\ **Post date:** [19 August 2005 06:59 UTC](https://rubytalk.org/t/ann-mockery-initial-release-yet-another-dynamic-mock-object-generator/20266/2 "2005-08-19T06:59:55Z")
Gary Shea schrieb: > Mockery ([http://rubyforge.org/projects/mockery\](http://rubyforge.org/projects/mockery%5C)) is a Ruby version of the > kind of dynamic mock generator that is commonplace in Java. The Java > versions tend to do a lousy job mocking classes as opposed to > interfaces, but we don't have that problem in Ruby (not only are there > no interfaces, but dynamic class modification is SO easy it's just not > an issue). > > A first draft of the above example using Mockery looks like: > >   ctl = Mockery::Controller.new(Some::Klass) >   ctl.record do |x| >     x.doit('blah') >   end >   ctl.try do |x| >     x.please\_call\_doit('blah') >   end >   assert\_equal(true, ctl.validate, ctl.error\_report) Nice work! I will try it if I need mocks in my unit tests. One first question: couldn't you put the last assert into the #try method? Something like    def try      ...    ensure      assert\_equal(true, validate, error\_report)    end Regards, Pit ---
**Author:** ![Gary\_Shea](https://avatars.discourse-cdn.com/v4/letter/g/779978/32.png) [@Gary\_Shea](https://rubytalk.org/u/Gary_Shea)\ **Post date:** [19 August 2005 14:16 UTC](https://rubytalk.org/t/ann-mockery-initial-release-yet-another-dynamic-mock-object-generator/20266/3 "2005-08-19T14:16:43Z")
I didn't even know you could do that, very slick. The only problem is that the idea of the #validate and #error\_report methods is to make #try independent of the choice of test framework. So we could do what you're saying, but we would have to create a new method:   def test\_unit\_try     ...   ensure     assert(validate, error\_report)   end and the module that defines that method would have to   require 'test/unit' which means a built-in dependency on Test::Unit. Still, it \_would\_ be convenient to not have to do the assert manually. A dumb-and-obvious way would be to have a subclass Mockery::TestUnitController of Mockery::Controller that just wraps #try as above. Unless I think of or hear a better idea I'll do that for the next release. Thanks!     Gary > **···** > > On Fri, 2005-08-19 at 15:59 +0900, Pit Capitain wrote: > > > Gary Shea schrieb: > > \> Mockery ([http://rubyforge.org/projects/mockery\](http://rubyforge.org/projects/mockery%5C)) is a Ruby version of the > > \> kind of dynamic mock generator that is commonplace in Java. The Java > > \> versions tend to do a lousy job mocking classes as opposed to > > \> interfaces, but we don't have that problem in Ruby (not only are there > > \> no interfaces, but dynamic class modification is SO easy it's just not > > \> an issue). > > \> > > \> A first draft of the above example using Mockery looks like: > > \> > > \> ctl = Mockery::Controller.new(Some::Klass) > > \> ctl.record do |x| > > \> x.doit('blah') > > \> end > > \> ctl.try do |x| > > \> x.please\_call\_doit('blah') > > \> end > > \> assert\_equal(true, ctl.validate, ctl.error\_report) > > > > Nice work! I will try it if I need mocks in my unit tests. One first > > question: couldn't you put the last assert into the #try method? > > Something like > > > >    def try > >      ... > >    ensure > >      assert\_equal(true, validate, error\_report) > >    end > > > > Regards, > > Pit