Using Mocker to Patch with Pytest
I Installed Pytest-Mock and Using a Mocker I Am Trying to Function as Patch Does, but I Get "Type Error: Need a Valid Target to Patch. You Supplied 'Return a +...
I installed pytest-mock and using a mocker I am trying to function as patch does, but I get "Type Error: Need a valid target to patch. You supplied 'return a + b'"
# test_capitalize.py
import time
def sum(a, b):
time.sleep(10)
return a + b
def test_sum(mocker):
mocker.patch('return a + b');
assertEqual(sum(2, 3), 9)
1 Answer
patch requires a path to the function being patched. You could do something like this:
import pytest
def sum(a, b):
return a + b
def test_sum1(mocker):
mocker.patch(__name__ + ".sum", return_value=9)
assert sum(2, 3) == 9
def test_sum2(mocker):
def crazy_sum(a, b):
return b + b
mocker.patch(__name__ + ".sum", side_effect=crazy_sum)
assert sum(2, 3) == 6
Result:
$ pytest -v patch_test.py
============= test session starts ==============
platform cygwin -- Python 3.6.4, pytest-3.10.1, py-1.7.0, pluggy-0.8.0 -- /usr/bin/python3
cachedir: .pytest_cache
rootdir: /home/xyz/temp, inifile:
plugins: mock-1.10.0, cov-2.6.0
collected 2 items
patch_test.py::test_sum1 PASSED [ 50%]
patch_test.py::test_sum2 PASSED [100%]
=========== 2 passed in 0.02 seconds ===========
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