Testing in Python
In Depth Mocking Example
How would you mock the func method?
from unittest import mock
class Test:
def __enter__(self):
return self
def __exit__(self, exc_type, exc_val, exc_tb):
pass
def hello(self):
return 1
def new_test():
return Test()
def func():
with new_test() as t:
return t.hello()
Answer
def test_TestWith():
test_hello_mock = mock.MagicMock(return_value=2)
test_enter_ret_mock = mock.MagicMock(
hello=test_hello_mock
)
test_enter_mock = mock.MagicMock(
return_value=test_enter_ret_mock
)
test_mock = mock.MagicMock(
__enter__=test_enter_mock,
__exit__=mock.MagicMock(return_value=None)
)
patcher = mock.patch("__main__.new_test", return_value=test_mock)
patcher.start()
ret = func()
test_mock.__enter__.assert_called_once()
test_mock.__exit__.assert_called_once()
assert ret == 2
patcher.stop()
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