python3Packages.charset-normalizer: add downstream tests

pkgs/development/python-modules/charset-normalizer/default.nix

@@ -3,6 +3,10 @@
 , fetchFromGitHub
 , pytestCheckHook
 , pythonOlder
+
+  # popular downstream dependencies
+, aiohttp
+, requests
 }:
 
 buildPythonPackage rec {
@@ -32,6 +36,8 @@ buildPythonPackage rec {
     "charset_normalizer"
   ];
 
+  passthru.tests = { inherit aiohttp requests; };
+
   meta = with lib; {
     description = "Python module for encoding and language detection";
     homepage = "https://charset-normalizer.readthedocs.io/";