Python mock Patch os.environ and return value
Solution 1:
You can try unittest.mock.patch.dict solution. Just call conn
with a dummy
argument:
import mysql.connector
import os, urlparse
@mock.patch.dict(os.environ, {"DATABASE_URL": "mytemp"}, clear=True) # why need clear=True explained here https://stackoverflow.com/a/67477901/248616
def conn(mock_A):
print os.environ["mytemp"]
if "DATABASE_URL" in os.environ:
url = urlparse(os.environ["DATABASE_URL"])
g.db = mysql.connector.connect(
user=url.username,
password=url.password,
host=url.hostname,
database=url.path[1:],
)
else:
return "Error"
Or if you don't want to modify your original function try this solution:
def func():
print os.environ["mytemp"]
def test_func():
k = mock.patch.dict(os.environ, {"mytemp": "mytemp"})
k.start()
func()
k.stop()
test_func()
Solution 2:
For this, I find that pytest's monkeypatch fixture leads to better code when you need to set environment variables:
def test_conn(monkeypatch):
monkeypatch.setenv('DATABASE_URL', '<URL WITH CREDENTIAL PARAMETERS>')
with patch(app.mysql.connector) as mock_mysql:
conn()
mock_mysql.connect.assert_called_with(<CREDENTIAL PARAMETERS>)
Solution 3:
The accepted answer is correct. Here's a decorator @mockenv
to do the same.
def mockenv(**envvars):
return mock.patch.dict(os.environ, envvars)
@mockenv(DATABASE_URL="foo", EMAIL="[email protected]")
def test_something():
assert os.getenv("DATABASE_URL") == "foo"
Solution 4:
In my use case, I was trying to mock having NO environmental variable set. To do that, make sure you add clear=True
to your patch.
with patch.dict(os.environ, {}, clear=True):
func()