Simplify pypy tests

Author: hynek

tox.ini

@@ -4,7 +4,7 @@ env_list =
     pre-commit,
     py3{8,9,10,11,12,13}-tests,
     py3{10,11,12,13}-mypy,
-    pypy3,
+    pypy3-tests,
     pyright,
     docs{,-sponsors},
     changelog,
@@ -26,6 +26,10 @@ commands =
     mypy: mypy tests/typing_example.py
     mypy: mypy src/attrs/__init__.pyi src/attr/__init__.pyi src/attr/_typing_compat.pyi src/attr/_version_info.pyi src/attr/converters.pyi src/attr/exceptions.pyi src/attr/filters.pyi src/attr/setters.pyi src/attr/validators.pyi
 
+[testenv:pypy3-tests]
+extras = tests
+commands = pytest tests/test_functional.py
+
 [testenv:py3{8,10,13}-tests]
 extras = cov
 # Python 3.6+ has a number of compile-time warnings on invalid string escapes.