Fix: if/else scope in assert statements

[colidyre]

There are some problematic cases in the tests. For example this code:

for i in range(0, 10):
    response = client.get("/t1")
    assert response.status_code == 200 if i < 5 else 429

(see: https://github.com/laurentS/slowapi/blob/master/tests/test_fastapi_extension.py#L23)

means probably check if the status_code is 200 for the first 5 requests, but the following requests should have the status code 429 (too many requests). This looks right at the first glance, but sadly this is not true:

A statement like assert x == 1 if False else "foobar" will be evaluated to assert "foobar", which is always True. This means that checking for a response status code like assert status_code == 200 if i < 5 else 429 will be evaluated to assert status_code == 200 for i < 5, but also to assert 429 (which will be evaluated to True in all circumstances) for i >= 5 and not assert status_code == 429 (which will really check for status code 429).

The fix is to get the right scope for the if/else condition by using parentheses, so that the right response status code will be checked if i >= 5.

Luckily, the tests are still green. So there is no impact and the status_code is really 429 for all cases before and after the fix.

Side note:

In cases like assert response.headers.get("Retry-After") if i < 5 else True or similar I assume that the else True case means simply skip the test after 5 requests by saying that the test is successful. A better understanding is imo given, if you're not using inline if/else statements and instead using constructs like this:

for i in range(0,10):
    response = client.get("/t1")
    if i < 5:
        assert ...

or maybe even better to only iterate 5 times by doing for i in range(0, 5): and skip the if part completely.

But I would be happy if you accept my PR and do the proposed refactoring in another PR instead.