def test_again():
res = app.do_something() # it is still test_1.json
...
def test_app():
app.data_file = 'test_1.json' # manually overwrite
res = app.do_something() # it is now test_1.json
...
def test_again():
res = app.do_something() # back to the original value
...
def test_sum(monkeypatch):
monkeypatch.setattr(app, 'data_file', 'test_1.json')
res = app.do_something() # It is now test_1.json
...
def test_sum(monkeypatch, tmpdir):
fake_file = tmpdir.join('test_1.json')
monkeypatch.setattr(app, 'data_file', fake_file)
res = app.do_something()
...
import app app.do_something()
def test_something():
assert do_something()