How to assert certain method is called with Ruby minitest framework?

Question

I want to test whether a function invokes other functions properly with minitest Ruby, but I cannot find a proper assert to test from the doc.

The source code

class SomeClass   def invoke_function(name)     name == "right" ? right () : wrong ()   end    def right     #...   end    def wrong     #...   end end 

The test code:

describe SomeClass do   it "should invoke right function" do     # assert right() is called   end    it "should invoke other function" do     # assert wrong() is called   end end 

Answer 1

Minitest has a special .expect :call for checking if some method is called.

describe SomeClass do   it "should invoke right function" do     mocked_method = MiniTest::Mock.new     mocked_method.expect :call, return_value, []     some_instance = SomeClass.new     some_instance.stub :right, mocked_method do       some_instance.invoke_function("right")     end     mocked_method.verify   end end 

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