How to assert if file does not exist in Pytest?

Question

I know how to assert if a file does exist, but not sure what the best way to do it is if it doesn't exist. I'm using pytest.

I have this so far, but this asserts if file does exist. I thought maybe using ! or not but not sure what the standard way to do it is. Bit of a noob. Thanks!

    path = os.path.join("cs.log")
    assert not path.is_file()

https://stackoverflow.com/questions/82831/how-do-i-check-whether-a-file-exists-without-exceptions — dosas, May 12 '21 at 10:45
hmm but what's the `not` of that? i.e. does not exist? and how do I assert that? — caasswa, May 12 '21 at 10:50
The link you supplied only shows how to check a file exists, not if a file doesn't exist. — caasswa, May 12 '21 at 10:57

score 13 · Accepted Answer · answered May 12 '21 at 10:46

13

if not os.path.exists("cs.log"):
    #stuff
    pass

Or, using assert:

assert os.path.exists("cs.log") == False

answered May 12 '21 at 10:46

Synthase

5,849
2
12
34

would that assert though? I want it to assert as it's a unit test – caasswa May 12 '21 at 10:50
See my edit for assert. Not sure that would make any diff anyway – Synthase May 12 '21 at 10:50
Thanks :) I'll try the latter even if it wouldn't make a difference :) – caasswa May 12 '21 at 10:53

How to assert if file does not exist in Pytest?

1 Answers1