[Tooling] Initial implementation of stub checker

requirements-dev.txt

@@ -0,0 +1,3 @@
+# compare blinka's implementation vs the stubs coming from CircuitPython's implementation
+circuitpython-stubs
+mypy

requirements-dev.txt.license

@@ -0,0 +1,3 @@
+# SPDX-FileCopyrightText: 2021 Melissa LeBlanc-Williams for Adafruit Industries
+#
+# SPDX-License-Identifier: MIT

test/stubtest.py

@@ -0,0 +1,49 @@
+"""Compare Blinka's implementation vs CircuitPython's stubs.
+
+To do this, we use MyPy's stubtest... But we invoke it from this file, instead
+of running it directly, so that we can set a specific target board and whatnot. Also
+makes it easier to iterate the whole src/ folder and run the tool on each and every file.
+"""
+
+import os
+import sys
+from pathlib import Path
+
+from mypy import stubtest
+
+SRC = Path(__file__).parent.parent / "src"
+sys.argv = [
+    "stubtest",
+    # run on all files
+    *(path.stem for path in SRC.glob("*.py")),
+    # shorter output (1 line instead of 5?) per error
+    "--concise",
+    # do not error about things on Blinka that arent on stubs
+    "--ignore-missing-stub",
+]
+
+def main() -> int:
+    """Run tests and return 0 on success, 1 in error."""
+    for target in [
+        "BLINKA_OS_AGNOSTIC",
+        # add more things here ??
+    ]:
+        msg = f"Running for: {target}"
+        print(msg, "=" * len(msg), sep="\n")
+
+        os.environ["BLINKA_FORCECHIP"] = target
+
+        # potentially some unittest.mock.patch or the like, to get code running
+
+        # TODO(elpekenin): pass arguments to this script? eg --failfast to control
+        # whether this quitting is performed or not
+        ret = stubtest.main()
+        if ret != 0:
+            return ret
+
+    # yay, no test failed
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())