Perform strict mypy typing check (#20)

.github/workflows/ci.yaml

@@ -18,7 +18,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - run: python -m pip install -U mypy
-      - run: python -m mypy -p aioraven
+      - run: python -m mypy -p aioraven --strict
   pydocstyle:
     runs-on: ubuntu-latest
     steps:

aioraven/data.py

@@ -72,7 +72,7 @@ def convert_datetime(
     raw: Optional[str],
     utc: bool = False
 ) -> Optional[datetime]:
-    if raw is not None and raw != 0xffffff:
+    if raw is not None and raw != '0xffffff':
         value = datetime(
             2000, 1, 1, 0, 0,
             tzinfo=timezone.utc if utc else None)

aioraven/serial.py

@@ -7,7 +7,7 @@
 from typing import Tuple
 
 from aioraven.protocols import RAVEnReaderProtocol
-from aioraven.streams import RAVEnReader
+from aioraven.reader import RAVEnReader
 from aioraven.streams import RAVEnStreamDevice
 from aioraven.streams import RAVEnWriter
 from serial_asyncio import create_serial_connection

aioraven/streams.py

@@ -91,7 +91,10 @@ async def open_connection(
     return reader, writer
 
 
-class RAVEnStreamDevice(RAVEnBaseDevice, AbstractAsyncContextManager):
+class RAVEnStreamDevice(
+    RAVEnBaseDevice,
+    AbstractAsyncContextManager['RAVEnStreamDevice']
+):
     """Read and write coordination for stream-based RAVEn devices."""
 
     _reader: Optional[RAVEnReader] = None
@@ -138,11 +141,16 @@ async def _query(
         self._writer.write_cmd(cmd_name, args)
         return await waiter if waiter is not None else None
 
-    async def __aenter__(self):
+    async def __aenter__(self) -> 'RAVEnStreamDevice':
         await self.open()
         return self
 
-    async def __aexit__(self, exc_type, exc_value, traceback):
+    async def __aexit__(
+        self,
+        exc_type: Any,
+        exc_value: Any,
+        traceback: Any
+    ) -> None:
         await self.close()