added extra info for set error

src/dodal/devices/current_amplifiers/femto.py

@@ -92,7 +92,11 @@ def __init__(
     @AsyncStatus.wrap
     async def set(self, value) -> None:
         if value not in [item.value for item in self.gain_conversion_table]:
-            raise ValueError(f"Gain value {value} is not within {self.name} range.")
+            raise ValueError(
+                f"Gain value {value} is not within {self.name} range."
+                + "\n Available gain:"
+                + f" {[f'{c.value:.0e}' for c in self.gain_conversion_table]}"
+            )
         sen_setting = self.gain_conversion_table(value).name
         LOGGER.info(f"{self.name} gain change to {sen_setting}:{value}")
 

src/dodal/devices/current_amplifiers/sr570.py

@@ -157,7 +157,11 @@ def __init__(
     @AsyncStatus.wrap
     async def set(self, value) -> None:
         if value not in [item.value for item in self.gain_conversion_table]:
-            raise ValueError(f"Gain value {value} is not within {self.name} range.")
+            raise ValueError(
+                f"Gain value {value} is not within {self.name} range."
+                + "\n Available gain:"
+                + f" {[f'{c.value:.0e}' for c in self.gain_conversion_table]}"
+            )
         sen_setting = self.gain_conversion_table(value).name
         LOGGER.info(f"{self.name} gain change to {value}")
 

tests/devices/unit_tests/current_amplifier/test_SR570.py

@@ -114,7 +114,13 @@ async def test_sr570_set(
 async def test_sr570_set_fail_out_of_range(sleep: AsyncMock, mock_sr570: SR570, gain):
     with pytest.raises(ValueError) as e:
         await mock_sr570.set(gain)
-    assert str(e.value) == f"Gain value {gain} is not within {mock_sr570.name} range."
+
+    assert (
+        str(e.value)
+        == f"Gain value {gain} is not within {mock_sr570.name} range."
+        + "\n Available gain:"
+        + f" {[f'{c.value:.0e}' for c in mock_sr570.gain_conversion_table]}"
+    )
     sleep.assert_not_called()
 
 

tests/devices/unit_tests/current_amplifier/test_femto.py

@@ -114,7 +114,12 @@ async def test_femto_set_fail_out_of_range(
 ):
     with pytest.raises(ValueError) as e:
         await mock_femto.set(gain)
-    assert str(e.value) == f"Gain value {gain} is not within {mock_femto.name} range."
+    assert (
+        str(e.value)
+        == f"Gain value {gain} is not within {mock_femto.name} range."
+        + "\n Available gain:"
+        + f" {[f'{c.value:.0e}' for c in mock_femto.gain_conversion_table]}"
+    )
     get_mock_put(mock_femto.gain).assert_not_called()
     sleep.assert_not_called()