Refactor ForcedPhotImageTask.runDataRef to new run.

python/lsst/meas/base/forcedPhotImage.py

@@ -121,17 +121,14 @@ def __init__(self, butler=None, refSchema=None, **kwds):
         self.makeSubtask('catalogCalculation', schema=self.measurement.schema)
 
     def runDataRef(self, dataRef, psfCache=None):
-        """!Measure a single exposure using forced detection for a reference catalog.
+        """!Measure a single exposure for forced detection for a reference catalog using a dataRef.
 
         @param[in]  dataRef   An lsst.daf.persistence.ButlerDataRef. It is passed to the
                               references subtask to obtain the reference WCS, the getExposure()
                               method (implemented by derived classes) to read the measurement
                               image, and the fetchReferences() method (implemented by derived
                               classes) to get the exposure and load the reference catalog (see
-                              the CoaddSrcReferencesTask for more information).  Sources are
-                              generated with generateMeasCat() in the measurement subtask.  These
-                              are passed to measurement's run method which fills the source
-                              catalog with the forced measurement results.  The sources are then
+                              the CoaddSrcReferencesTask for more information).  The sources are then
                               passed to the writeOutputs() method (implemented by derived classes)
                               which writes the outputs.  See derived class documentation for which
                               datasets and data ID keys are used.
@@ -143,21 +140,40 @@ def runDataRef(self, dataRef, psfCache=None):
         if psfCache is not None:
             exposure.getPsf().setCacheSize(psfCache)
         refCat = self.fetchReferences(dataRef, exposure)
+
         measCat = self.measurement.generateMeasCat(exposure, refCat, refWcs,
                                                    idFactory=self.makeIdFactory(dataRef))
         self.log.info("Performing forced measurement on %s" % (dataRef.dataId,))
         self.attachFootprints(measCat, refCat, exposure, refWcs, dataRef)
 
-        self.measurement.run(measCat, exposure, refCat, refWcs, exposureId=self.getExposureId(dataRef))
+        exposureId = self.getExposureId(dataRef)
+
+        forcedPhotResult = self.run(measCat, exposure, refCat, refWcs, exposureId=exposureId)
+
+        self.writeOutput(dataRef, forcedPhotResult.measCat)
 
+    def run(self, measCat, exposure, refCat, refWcs, exposureId=None):
+        """!Measure a single exposure with forced detection for a reference catalog.
+
+        @param[in]  measCat    The measurement catalog generated by measurement.generateMeasCat(),
+                               based on the sources listed in the reference catalog.
+        @param[in]  exposure   The measurement image upon which to perform forced detection.
+        @param[in]  refCat     The reference catalog of sources to measure.
+        @param[in]  refWcs     The WCS for the references.
+        @param[in]  exposureId Optional unique exposureId used for random seed in measurement task.
+
+        @return     result     An lsst.pipe.base.Struct containing the catalog of forced measurement results
+                               from measurement.run().
+        """
+        self.measurement.run(measCat, exposure, refCat, refWcs, exposureId=exposureId)
         if self.config.doApCorr:
             self.applyApCorr.run(
                 catalog=measCat,
                 apCorrMap=exposure.getInfo().getApCorrMap()
             )
         self.catalogCalculation.run(measCat)
 
-        self.writeOutput(dataRef, measCat)
+        return lsst.pipe.base.Struct(measCat=measCat)
 
     def makeIdFactory(self, dataRef):
         """!Hook for derived classes to define how to make an IdFactory for forced sources.