Fix mypy issues on windows

tests/tests/test_database_backend.py

@@ -1199,6 +1199,15 @@ def start_worker(
         self.processes.append(p)
         return p
 
+    @staticmethod
+    def _get_ctrl_c_signal() -> int:
+        """
+        Windows uses a different signal for CTRL-C than Unix.
+        """
+        if hasattr(signal, "CTRL_C_EVENT"):
+            return cast(int, signal.CTRL_C_EVENT)
+        return signal.SIGINT
+
     def test_run_subprocess(self) -> None:
         result = test_tasks.noop_task.enqueue()
         process = self.start_worker(["--batch"])
@@ -1223,7 +1232,7 @@ def test_interrupt_no_tasks(self) -> None:
 
     def test_interrupt_signals(self) -> None:
         for sig in [
-            signal.CTRL_C_EVENT if sys.platform == "win32" else signal.SIGINT,  # type:ignore[attr-defined]
+            self._get_ctrl_c_signal(),
             signal.SIGTERM,
         ]:
             with self.subTest(sig):
@@ -1248,9 +1257,7 @@ def test_interrupt_signals(self) -> None:
                 self.assertEqual(result.status, ResultStatus.COMPLETE)
 
     def test_repeat_ctrl_c(self) -> None:
-        ctrl_c_signal = (
-            signal.CTRL_C_EVENT if sys.platform == "win32" else signal.SIGINT  # type:ignore[attr-defined]
-        )
+        ctrl_c_signal = self._get_ctrl_c_signal()
 
         result = test_tasks.hang.enqueue()