BUG - Understand why the tests are failing with httpx==0.28.1

[LeoGrin]

See #51 and #49 for context. For now we enforce httpx==0.27.2 but we should be able to use newer version in the future.

[LeoGrin]

Only looked quickly but this may be related encode/httpx#3433

[mert-kurttutan]

Hi, @LeoGrin
This is due to the handling of spaces in httpx: Two relevant commits:

• Use '%20' for encoding spaces in query parameters. encode/httpx#2543
• Review urlescape percent-safe set, and use + behavior for form spaces. encode/httpx#3373
  Where they changed from %20 -> + -> %20 for handling spaces in json->url conversion.

Two potential solutions:

• change the test assertions so that it handles this based on the version of httpx available.
• some other library that is consistent with this, e.g. requests

I prefer the 1st solution since the 2nd is longer and inconsistency in url encoding only affect this test result

[mert-kurttutan]

The responsible change is about the function urlencode
https://github.com/encode/httpx/pull/2543/files#diff-f1eb4e8fbdbce3bb7dcc3ecb662f690f9443599de8b172513ddb65de6b1d7c73
where they changed it between their own version and the one from standard library