Add explicit timeouts for the monitor tests

tests/__init__.py

@@ -1,12 +1,53 @@
 # Copyright (c) 2020 OpenCyphal
 # This software is distributed under the terms of the MIT License.
 # Author: Pavel Kirienko <[email protected]>
+# pylint: disable=wrong-import-position
 
-import pathlib
+from pathlib import Path
+from typing import Callable, TypeVar, Any
 
 # Please maintain these carefully if you're changing the project's directory structure.
-TEST_DIR = pathlib.Path(__file__).resolve().parent
+TEST_DIR = Path(__file__).resolve().parent
 ROOT_DIR = TEST_DIR.parent
 
 DEPS_DIR = TEST_DIR / "deps"
 assert DEPS_DIR.is_dir()
+
+
+T = TypeVar("T")
+
+
+def timeout(seconds: int) -> Callable[[Callable[..., T]], Callable[..., T]]:
+    """
+    This is a decorator that makes the function raise :class:`TimeoutError` if it takes more than ``seconds``
+    seconds to complete.
+
+    >>> import time
+    >>> @timeout(3)
+    ... def runas(delay: float) -> None:
+    ...     time.sleep(delay)
+    >>> runas(1)
+    >>> runas(10)
+    Traceback (most recent call last):
+      ...
+    TimeoutError: ...
+    """
+    import signal
+    from functools import wraps
+
+    def decorator(fun: Callable[..., T]) -> Callable[..., T]:
+        @wraps(fun)
+        def wrapper(*args: Any, **kwargs: Any) -> T:
+            def signal_handler(_signum: int, _frame: Any) -> None:
+                raise TimeoutError(f"Function {fun} took more than {seconds:.0f}s to complete")
+
+            signal.signal(signal.SIGALRM, signal_handler)
+            signal.alarm(seconds)
+            try:
+                return fun(*args, **kwargs)
+            finally:
+                signal.alarm(0)
+
+        return wrapper
+
+    return decorator

tests/cmd/monitor.py

@@ -18,10 +18,12 @@
 from pycyphal.transport.udp import UDPTransport
 from tests.subprocess import Subprocess
 from tests.dsdl import OUTPUT_DIR
+from tests import timeout
 import yakut
 
 
 # noinspection SpellCheckingInspection
+@timeout(300)
 @pytest.mark.asyncio
 async def _unittest_monitor_nodes(compiled_dsdl: Any) -> None:
     _ = compiled_dsdl
@@ -110,6 +112,7 @@ async def _unittest_monitor_nodes(compiled_dsdl: Any) -> None:
 
 
 # noinspection SpellCheckingInspection
+@timeout(60)
 @pytest.mark.asyncio
 async def _unittest_monitor_errors(compiled_dsdl: Any) -> None:
     _ = compiled_dsdl