Mocking python function based on input arguments

Question

We have been using Mock for python for a while.

Now, we have a situation in which we want to mock a function

def foo(self, my_param):
    #do someth         


        

Answer 1

I've ended up here looking for "how to mock a function based on input arguments" and I finally solved this creating a simple aux function:

def mock_responses(responses, default_response=None):
  return lambda input: responses[input] if input in responses else default_response

Now:

my_mock.foo.side_effect = mock_responses(
  {
    'x': 42, 
    'y': [1,2,3]
  })
my_mock.goo.side_effect = mock_responses(
  {
    'hello': 'world'
  }, 
  default_response='hi')
...

my_mock.foo('x') # => 42
my_mock.foo('y') # => [1,2,3]
my_mock.foo('unknown') # => None

my_mock.goo('hello') # => 'world'
my_mock.goo('ey') # => 'hi'

Hope this will help someone!