check for placement node that matches uri before creating one (#55)

* check for placement node that matches uri before creating one

* add missing quotes, fix for py2

* remove f

* Fix coveralls on Python 3.6 (#52)

* Enable automated unit testing with Python 3.12 (#56)

* Fix coveralls on Python 3.6

* Enable automated unit testing with Python 3.12

* Only trigger a production PyPi build on tags using semantic versioning (#57)

* Use latest versions of GitHub workflow actions, build with Python 3.12 (#58)

* Enable automated unit testing for Python 3.5 (#59)

* Fix coveralls parallel builds (#61)

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Co-authored-by: Scott Small <scott.small@semaphoresolutions.ca>

s4/clarity/step.py

@@ -534,7 +534,9 @@ def create_placement(self, artifact, container, well_string):
         :param well_string: The location on the plate to place the artifact
         """
         placement_root = self.xml_root.find("./output-placements")
-        placement_node = ETree.SubElement(placement_root, "output-placement", {"uri": artifact.uri})
+        placement_node = self.xml_root.find("./output-placements/output-placement[@uri='" + artifact.uri + "']")
+        if not placement_node:
+            placement_node = ETree.SubElement(placement_root, "output-placement", {"uri": artifact.uri})
         location_subnode = ETree.SubElement(placement_node, "location")
         ETree.SubElement(location_subnode, "container", {"uri": container.uri})
         ETree.SubElement(location_subnode, "value").text = well_string