Disable type checking tests for <= 3.9

.github/workflows/ci.yml

@@ -16,9 +16,9 @@ jobs:
         python:
           - '3.11'
           - '3.10'
-          # - '3.9'
-          # - '3.8'
-          # - '3.7'
+          - '3.9'
+          - '3.8'
+          - '3.7'
     name: Python ${{ matrix.python }}
     steps:
       # Python
@@ -46,7 +46,14 @@ jobs:
 
       # Tests
       - name: Run tests
-        run: pytest --ignore=tests/test_pattern_matching.py
+        run: pytest --ignore=tests/test_pattern_matching.py --ignore=tests/type-checking/test_result.yml
+      - name: Run tests (type checking)
+        if: matrix.python != '3.7' && matrix.python != '3.8' && matrix.python != '3.9'
+        # These started breaking for <= 3.9, due to the type checker using a
+        # '|' for unions rather than 'Union[...]', so it's not possible to run
+        # the tests without maintaining two duplicate files (one for <= 3.9 and
+        # one for > 3.9)
+        run: pytest tests/type-checking/test_result.yml
       - name: Run tests (pattern matching)
         if: matrix.python == '3.10' || matrix.python == '3.11'
         run: pytest tests/test_pattern_matching.py