add read_one and supporting methods

src/pms/core/reader.py

@@ -61,6 +61,15 @@ def __call__(self, *, raw: bool | None = None) -> Iterator[RawData | ObsData]:
         """
         ...
 
+    def start(self) -> None:
+        self.__enter__()
+
+    def read_one(self, *, raw: bool | None = None) -> RawData | ObsData:
+        return next(self(raw=raw))
+
+    def stop(self) -> None:
+        self.__exit__(None, None, None)
+
 
 class SensorReader(Reader):
     """Read sensor messages from serial port

tests/core/test_reader.py

@@ -9,20 +9,17 @@ class MockReader(reader.Reader):
     def __init__(self, raise_on_enter=False):
         self.raise_on_enter = raise_on_enter
 
-    def read_one(self):
-        raise NotImplemented
-
     def __call__(self):
         raise NotImplemented
 
-    def open(self):
+    def __exit__(self, *args, **kwargs):
+        self.exited = True
+
+    def __enter__(self):
         if self.raise_on_enter:
             raise reader.UnableToRead()
         self.entered = True
 
-    def close(self):
-        self.exited = True
-
 
 @pytest.fixture
 def mock_sleep(monkeypatch):