Make FracUpdatedMetricTask return None for first dataId.

lsst · Oct 10, 2019 · 5d212e4 · 5d212e4
1 parent df6da79
commit 5d212e4
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Showing 2 changed files with 5 additions and 4 deletions.
diff --git a/python/lsst/ap/association/metrics.py b/python/lsst/ap/association/metrics.py
@@ -171,8 +171,7 @@ def makeMeasurement(self, values):
                                              "or numUnassociatedDiaObjects") from e
             else:
                 if nUpdated <= 0 and nUnassociated <= 0:
-                    raise MetricComputationError(
-                        "No pre-existing DIAObjects; can't compute updated fraction.")
+                    return None  # No pre-existing DIAObjects; no fraction to compute
                 else:
                     fraction = nUpdated / (nUpdated + nUnassociated)
                     return Measurement(self.getOutputMetricName(self.config),

diff --git a/tests/test_metrics.py b/tests/test_metrics.py
@@ -164,8 +164,10 @@ def testAllUpdated(self):
 
     def testNoObjects(self):
         metadata = _makeAssociationMetadata(numUpdated=0, numUnassociated=0)
-        with self.assertRaises(MetricComputationError):
-            self.task.run(metadata)
+        result = self.task.run(metadata)
+        meas = result.measurement
+
+        self.assertIsNone(meas)
 
     def testMissingData(self):
         result = self.task.run(None)