run mypy

.github/workflows/ci.yaml

@@ -69,8 +69,9 @@ jobs:
       - name: Install dependencies
         run: >
           apt-get update &&
-          apt-get install --no-install-recommends --yes black isort pylint
-          python3 python3-coverage python3-flake8 python3-ruamel.yaml shellcheck
+          apt-get install --no-install-recommends --yes black isort mypy pylint
+          python3 python3-coverage python3-flake8 python3-ruamel.yaml
+          python3-setuptools python3-typeshed shellcheck
       - uses: actions/checkout@v4
       - name: Run unit tests
         run: |
@@ -103,8 +104,9 @@ jobs:
       - name: Install dependencies
         run: >
           apt-get update &&
-          apt-get install --no-install-recommends --yes pylint python3
-          python3-coverage python3-ruamel.yaml
+          apt-get install --no-install-recommends --yes mypy pylint python3
+          python3-coverage python3-ruamel.yaml python3-setuptools
+          python3-typeshed
       - uses: actions/checkout@v4
       - name: Run unit tests
         run: |

tests/test_mypy.py

@@ -0,0 +1,56 @@
+# Copyright (C) 2023, Benjamin Drung <[email protected]>
+#
+# Permission to use, copy, modify, and/or distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+# REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+# AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+# INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+# LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+# OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+# PERFORMANCE OF THIS SOFTWARE.
+
+"""Run mypy to check static typing of the Python code."""
+
+import subprocess
+import sys
+import unittest
+
+import ruamel.yaml
+
+from . import get_source_files, unittest_verbosity
+
+
+class MypyTestCase(unittest.TestCase):
+    """
+    This unittest class provides a test that runs mypy to check static
+    typing of the Python code. The list of source files is provided by
+    the get_source_files() function.
+    """
+
+    def test_mypy(self) -> None:
+        """Test: Run mypy on Python source code."""
+        if [int(x) for x in ruamel.yaml.__version__.split(".")] < [0, 18]:
+            self.skipTest("false positives with ruamel.yaml < 0.18")
+        cmd = ["mypy", "--strict"] + get_source_files()
+        if unittest_verbosity() >= 2:
+            sys.stderr.write(f"Running following command:\n{' '.join(cmd)}\n")
+        process = subprocess.run(cmd, capture_output=True, check=False, text=True)
+
+        if process.returncode != 0:  # pragma: no cover
+            msgs = []
+            if process.stderr:
+                msgs.append(
+                    f"mypy exited with code {process.returncode} and has"
+                    f" unexpected output on stderr:\n{process.stderr.rstrip()}"
+                )
+            if process.stdout:
+                msgs.append(f"mypy found issues:\n{process.stdout.rstrip()}")
+            if not msgs:
+                msgs.append(
+                    f"mypy exited with code {process.returncode} "
+                    "and has no output on stdout or stderr."
+                )
+            self.fail("\n".join(msgs))