Add test for error reporting in AT prepare_for_flat

python/lsst/ts/observatory/control/auxtel/atcalsys.py

@@ -231,7 +231,7 @@ async def prepare_for_flat(self, sequence_name: str) -> None:
             task_setup_electrometer,
             return_exceptions=True,
         )
-        operations = ["Setup monochromator", "Setup latiss", "Setup electrometer"]
+        operations = ["Setup monochromator", "Setup latiss", "Setup electrometers"]
         exceptions = [
             (operation, value)
             for (operation, value) in zip(operations, return_values)
@@ -241,7 +241,7 @@ async def prepare_for_flat(self, sequence_name: str) -> None:
         if exceptions:
             err_message = f"{len(exceptions)} out of {len(operations)} failed.\n"
             for operation, exception in exceptions:
-                err_message += f"{operation} failed with '{exception!r}'.\n"
+                err_message += f"{operation} failed with {exception!r}.\n"
             raise RuntimeError(err_message)
 
     async def calculate_optimized_exposure_times(

tests/auxtel/test_atcalsys.py

@@ -20,6 +20,7 @@
 
 import asyncio
 import logging
+import re
 import types
 import unittest.mock
 
@@ -153,6 +154,33 @@ async def test_prepare_for_flat(self) -> None:
             timeout=mock_latiss.long_timeout,
         )
 
+    async def test_prepare_for_flat_with_exceptions(self) -> None:
+        latiss_exception = RuntimeError("Error in LATISS")
+        monochromator_exception = RuntimeError("Error in monochromator")
+        electrometers_exception = RuntimeError("Error in electrometers")
+
+        self.atcalsys.latiss = unittest.mock.AsyncMock()
+        self.atcalsys.latiss.setup_instrument = unittest.mock.AsyncMock(
+            side_effect=latiss_exception
+        )
+        self.atcalsys.rem.atmonochromator.cmd_updateMonochromatorSetup.set_start = (
+            unittest.mock.AsyncMock(side_effect=monochromator_exception)
+        )
+        self.atcalsys.setup_electrometers = unittest.mock.AsyncMock(
+            side_effect=electrometers_exception
+        )
+
+        with pytest.raises(
+            RuntimeError,
+            match=re.escape(
+                "3 out of 3 failed.\n"
+                f"Setup monochromator failed with {monochromator_exception!r}.\n"
+                f"Setup latiss failed with {latiss_exception!r}.\n"
+                f"Setup electrometers failed with {electrometers_exception!r}.\n"
+            ),
+        ):
+            await self.atcalsys.prepare_for_flat("at_whitelight_r")
+
     async def mock_end_readout(
         self, flush: bool, timeout: float
     ) -> types.SimpleNamespace: