mypy_test.py: Move type-checking of our tests and scripts into a different test (#8587)

.github/workflows/tests.yml

@@ -61,7 +61,7 @@ jobs:
       - run: ./tests/pytype_test.py --print-stderr
 
   mypy:
-    name: Run mypy against typeshed
+    name: Test the stubs with mypy
     runs-on: ubuntu-latest
     strategy:
       matrix:
@@ -77,7 +77,7 @@ jobs:
       - run: ./tests/mypy_test.py --platform=${{ matrix.platform }} --python-version=${{ matrix.python-version }}
 
   pyright:
-    name: Run pyright against typeshed
+    name: Test the stubs with pyright
     runs-on: ubuntu-latest
     strategy:
       matrix:

.github/workflows/typecheck_typeshed_code.yml

@@ -0,0 +1,36 @@
+name: Typecheck-typeshed-code
+
+on:
+  workflow_dispatch:
+  push:
+    branches:
+      - main
+      - master
+  pull_request:
+    paths:
+      - 'scripts/**'
+      - 'tests/**'
+      - '.github/workflows/typecheck_typeshed_code.yml'
+      - 'requirements-tests.txt'
+
+permissions:
+  contents: read
+
+env:
+  PIP_DISABLE_PIP_VERSION_CHECK: 1
+
+jobs:
+  mypy:
+    name: Run mypy against the scripts and tests directories
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        platform: ["linux", "win32"]
+      fail-fast: false
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v4
+        with:
+          python-version: 3.9
+      - run: pip install -r requirements-tests.txt
+      - run: python ./tests/typecheck_typeshed.py --platform=${{ matrix.platform }}