Mock is a doubles (stubs and mocks) library for Crystal, inspired by the API of rspec-mocks (but it implements a small basic subset of it to the date).

Add this to your application's shard.yml:

development_dependencies:
  mock:
    github: porras/mock

You can now run shards to install it.

Require it in your tests and you can start using it.

require "mock"

Just call the double() method.

Calling stub on that double object will set a method stub:

my_object = double()
my_object.stub(:my_method)

You can establish a return value for the stub method (if you don't, method stubs return nil):

my_object = double()
my_object.stub(:my_method).and_return("my value")

my_object.my_method.should eq("my value")

You can also filter my arguments, establishing different stubs for the same method:

my_object = double()
my_object.stub(:my_method).with(1).and_return("value 1")
my_object.stub(:my_method).with(2).and_return("value 2")

my_object.my_method(1).should eq("value 1")
my_object.my_method(2).should eq("value 2")

You can also set the expectation that a method will be called, and it will be automatically checked at the end of the test:

my_object = double()
my_object.should_receive(:my_method).with(1).and_return("my value")

# if we omit this line, the test will fail
my_object.my_method(1).should eq("value 1")

See example_spec.cr for more examples.

1. Fork it ( https://github.com/porras/mock/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

This code is released under the MIT License.

• Sergio Gil