Await eiger_controller arm

src/ophyd_async/fastcs/eiger/_eiger_controller.py

@@ -5,6 +5,7 @@
     DetectorController,
     DetectorTrigger,
     TriggerInfo,
+    wait_for_value,
 )
 
 from ._eiger_io import EigerDriverIO, EigerTriggerMode
@@ -55,11 +56,13 @@ async def prepare(self, trigger_info: TriggerInfo):
         await asyncio.gather(*coros)
 
     async def arm(self):
-        self._arm_status = self._drv.detector.arm.trigger(timeout=DEFAULT_TIMEOUT)
+        # NOTE: This will return immedietly on FastCS 0.8.0,
+        # but will return after the Eiger has completed arming in 0.9.0.
+        # https://github.com/DiamondLightSource/FastCS/pull/141
+        await self._drv.detector.arm.trigger(timeout=DEFAULT_TIMEOUT)
 
     async def wait_for_idle(self):
-        if self._arm_status:
-            await self._arm_status
+        await wait_for_value(self._drv.detector.state, "idle", timeout=DEFAULT_TIMEOUT)
 
     async def disarm(self):
         await self._drv.detector.disarm.trigger()

tests/fastcs/eiger/test_eiger_controller.py

@@ -7,7 +7,7 @@
     init_devices,
 )
 from ophyd_async.fastcs.eiger import EigerController, EigerDriverIO
-from ophyd_async.testing import get_mock_put, set_mock_value
+from ophyd_async.testing import callback_on_mock_put, get_mock_put, set_mock_value
 
 DriverAndController = tuple[EigerDriverIO, EigerController]
 
@@ -18,6 +18,12 @@ def eiger_driver_and_controller_no_arm(RE) -> DriverAndController:
         driver = EigerDriverIO("")
         controller = EigerController(driver)
 
+    def become_idle_after_arm(*args, **kwargs):
+        # Mocking that eiger has armed and finished taking frames.
+        set_mock_value(driver.detector.state, "idle")
+
+    callback_on_mock_put(driver.detector.arm, become_idle_after_arm)
+
     return driver, controller