Add a mock interface, take two

turret_python_interface/mock_interface.py

@@ -0,0 +1,58 @@
+"""
+Provides a mock Interface class for testing purposes, to decouple tests from requiring
+the entire turret hardware stack.
+"""
+
+from math import tau, pi, sin
+from pathlib import Path
+from types import TracebackType
+from typing import Optional, Type
+
+from .interface import Interface
+from .datamodel.telemetry_packet import TelemetryPacket
+
+
+class MockInterface(Interface):
+    # noinspection PyMissingConstructor
+    def __init__(
+        self,
+        *,
+        serial_path: Path = Path("/") / "dev" / "ttyS0",
+        baud: int = 115200,
+        timeout=30,
+    ):
+        # NOTE: we intentionally don't call the constructor of the superclass as it would
+        #       init a serial connection; which is an implementation detail
+        #       and we cannot mock it effectively.
+        # NOTE: the internal data members of this type are not mocked, as they are implementation
+        #       details.  mocking them is unnecessary.
+        self.t = 0
+        ...
+
+    @property
+    def state(self) -> float:
+        # basically, we are reproducing a sine wave.
+        # Every time the state is observed, time progresses.
+
+        # preserve the current time
+        t = self.t
+        # increment t for the next tick
+        self.t += pi / 4
+        if self.t >= tau:
+            self.t = 0
+
+        return sin(t)
+
+    def __enter__(self) -> Interface:
+        ...
+
+    def __exit__(
+        self,
+        __exc_type: Optional[Type[BaseException]],
+        __exc_value: Optional[BaseException],
+        __traceback: Optional[TracebackType],
+    ) -> Optional[bool]:
+        ...
+
+    def get_telemetry(self) -> TelemetryPacket:
+        return TelemetryPacket(turret_pos=self.state)