assert-on-tuple / W0199

Message emitted:

Assert called on a populated tuple. Did you mean 'assert x,y'?

Description:

A call of assert on a tuple will always evaluate to true if the tuple is not empty, and will always evaluate to false if it is.

Problematic code:

assert (1, None)  # [assert-on-tuple]

Correct code:

x, y = (1, None)
assert x
assert y

Additional details:

Directly asserting a non-empty tuple will always pass. The solution is to

test something that could fail, or not assert at all.

For unittest assertions there is the similar redundant-unittest-assert / W1503 message.

Created by the basic checker.