Check method call on model using MiniTest

Question

If I was using RSpec I could test if a method is being called like so:

expect(obj).to receive(:method)

What is the equivalent in MiniTest?

Answer 1

For this purpose Minitest has a .expect :call which allows you to check if method is getting called:

describe Post do

  before do
    @post = FactoryGirl.build(:post)
  end

  describe "when saving" do
    it "calls the create_slug method before validation" do
      mock_method = MiniTest::Mock.new
      mock_method.expect :call, "return_value", []
      @post.stub :create_slug, mock_method do
        @post.save
      end
      mock_method.verify
    end
  end

end

If @post.create_slug was called, test will pass. Otherwise test will raise a MockExpectationError.

Unfortunately this feature is not documented very well. I found this answer from here: https://github.com/seattlerb/minitest/issues/216