Mock Python's built in print function

Question

I've tried

from mock import Mock import __builtin__  __builtin__.print = Mock() 

But that raises a syntax error. I've also tried patching it like so

@patch('__builtin__.print') def test_something_that_performs_lots_of_prints(self, mock_print):      # assert stuff 

Is there any way to do this?

Answer 1

I know that there is already an accepted answer but there is simpler solution for that problem - mocking the print in python 2.x. Answer is in the mock library tutorial: http://www.voidspace.org.uk/python/mock/patch.html and it is:

>>> from StringIO import StringIO >>> def foo(): ...     print 'Something' ... >>> @patch('sys.stdout', new_callable=StringIO) ... def test(mock_stdout): ...     foo() ...     assert mock_stdout.getvalue() == 'Something\n' ... >>> test() 

Of course you can use also following assertion:

self.assertEqual("Something\n", mock_stdout.getvalue()) 

I have checked this solution in my unittests and it is working as expected. Hope this helps somebody. Cheers!