Wait for Odin FAN in Eiger kickoff

src/ophyd_async/fastcs/eiger/_eiger.py

@@ -1,8 +1,10 @@
 from ophyd_async.core import (
+    DEFAULT_TIMEOUT,
     AsyncStatus,
     PathProvider,
     StandardDetector,
     TriggerInfo,
+    wait_for_value,
 )
 from ophyd_async.epics.odin import Odin, OdinWriter
 
@@ -41,3 +43,8 @@ def __init__(
     @AsyncStatus.wrap
     async def prepare(self, value: TriggerInfo) -> None:
         await super().prepare(value)
+
+    @AsyncStatus.wrap
+    async def kickoff(self) -> None:
+        await super().kickoff()
+        await wait_for_value(self.odin.fan_ready, 1, DEFAULT_TIMEOUT)

tests/fastcs/eiger/test_eiger_detector.py

@@ -18,6 +18,11 @@ def set_meta_filename_and_id(value, *args, **kwargs):
 
     callback_on_mock_put(detector.odin.file_name, set_meta_filename_and_id)
 
+    def set_odin_fan_ready(value, *args, **kwargs):
+        set_mock_value(detector.odin.fan_ready, 1)
+
+    callback_on_mock_put(detector.drv.detector.arm, set_odin_fan_ready)
+
     detector._writer._path_provider.return_value.filename = "filename.h5"  # type: ignore
 
     set_mock_value(detector.odin.meta_active, "Active")
@@ -43,3 +48,17 @@ async def test_when_prepared_eiger_bit_depth_is_passed_and_set_in_odin(detector)
     get_mock_put(detector.odin.data_type).assert_called_once_with(
         f"UInt{expected_datatype}", wait=True
     )
+
+
+async def test_when_kickoff_called_odin_fan_waited_for(
+    detector,
+):
+    await detector.prepare(
+        TriggerInfo(
+            exposure_timeout=None,
+            number_of_events=1,
+            trigger=DetectorTrigger.INTERNAL,
+        )
+    )
+    await detector.kickoff()
+    assert await detector.odin.fan_ready.get_value() == 1