test for empty pd config

Author: CamDavidsonPilon

core/pioreactor/background_jobs/od_reading.py

@@ -62,7 +62,6 @@
 from pioreactor import whoami
 from pioreactor.background_jobs.base import BackgroundJob
 from pioreactor.background_jobs.base import LoggerMixin
-from pioreactor.calibrations import load_active_calibration
 from pioreactor.config import config
 from pioreactor.pubsub import publish
 from pioreactor.states import JobState as st
@@ -1417,6 +1416,8 @@ def start_od_reading(
     # use an OD calibration?
     calibration_transformer: CalibrationTransformerProtocol
     if calibration is True:
+        from pioreactor.calibrations import load_active_calibration
+
         calibration_transformer = CachedCalibrationTransformer()
         for channel, angle in channel_angle_map.items():
             active_calibration = load_active_calibration(f"od{angle}")  # type: ignore

core/tests/test_od_reading.py

@@ -1453,6 +1453,29 @@ def test_can_pass_config_section_directly() -> None:
             assert set(od.channel_angle_map.keys()) == {"1"}
 
 
+def test_config_section_omits_empty_photodiode_channels() -> None:
+    experiment = "test_config_section_omits_empty_photodiode_channels"
+    with temporary_config_changes(
+        config,
+        [
+            ("od_config.photodiode_channel", "1", "REF"),
+            ("od_config.photodiode_channel", "2", "90"),
+            ("od_config.photodiode_channel", "3", ""),
+            ("od_config.photodiode_channel", "4", ""),
+        ],
+    ):
+        section = config["od_config.photodiode_channel"]
+        with start_od_reading(
+            section,
+            interval=None,
+            fake_data=True,
+            experiment=experiment,
+            calibration=False,
+        ) as od:
+            assert set(od.channel_angle_map.keys()) == {"2"}
+            assert set(od.adc_reader.channels) == {"1", "2"}
+
+
 def test_CachedCalibrationTransformer_with_real_calibration() -> None:
     calibration = structs.OD600Calibration(
         angle="90",