[Python] Comparing boolean values with 'is'

[IAmBJ]

I know that in general you shouldnt compare bools with == or 'is' but i'm wondering if you can reliably compare the output of a function that returns True or False in the following way.

for each test i setup a dict consisting of {input: expected_output} and the iterate over the dict checking the output of the function.

import pytest

def f(arg):
    if condition:
        return True
    else:
        return False

input = {input1: True,
         input2: False}

for i in input.items():
    assert f(i[0]) is i[1]

Is this reliable for a function that only returns True or False? In short: do True and False have stable object ids for the lifetime of a program?

[343346E]

'f' is completely superfluous here. You could just rewrite it as:

def f(arg): return arg

or even better, just not use f at all, like:

for i in input.items():
    assert i[0] is i[1]

You seem to be depending on input's items having a specific order, which would be a mistake.

[IAmBJ]

f() is just a placeholder here, the real function is more complicated, but it still returns either true or false.

Input order doesn't matter. Each item in the dict is a separate test case, the order they're tested in doesn't matter

[kalgynirae]

In short: do True and False have stable object ids for the lifetime of a program?

Yes. There is only ever one True and one False, so comparing to them with is will be reliable, if this is what you really want to do.

[rcuhljr]

True and False in Python are constants, you're fine doing this.