Label printing bug fixes (#7329)

* Hide printing actions button for top level stock location

* Fix typo

* Add another check for null

* Remove debug statement

* Prevent display of multiple form-error notifications

* Fix pickling for print offloading

* Reset selected plugin

* Exclude the entire 'context' object when pickling a printing job

src/backend/InvenTree/plugin/base/label/mixins.py

@@ -147,6 +147,9 @@ class LabelPrintingMixin:
 
         N = len(items)
 
+        if N <= 0:
+            raise ValidationError(_('No items provided to print'))
+
         # Generate a label output for each provided item
         for item in items:
             context = label.get_context(item, request)
@@ -177,9 +180,13 @@ class LabelPrintingMixin:
                 self.print_label(**print_args)
             else:
                 # Offload the print task to the background worker
-                # Exclude the 'pdf_file' object - cannot be pickled
 
-                kwargs.pop('pdf_file', None)
+                # Exclude the 'pdf_file' object - cannot be pickled
+                print_args.pop('pdf_file', None)
+
+                # Exclude the 'context' object - cannot be pickled
+                print_args.pop('context', None)
+
                 offload_task(plugin_label.print_label, self.plugin_slug(), **print_args)
 
             # Update the progress of the print job

src/backend/InvenTree/report/models.py

@@ -246,7 +246,6 @@ class ReportTemplateBase(MetadataMixin, InvenTree.models.InvenTreeModel):
             'base_url': get_base_url(request=request),
             'date': InvenTree.helpers.current_date(),
             'datetime': InvenTree.helpers.current_time(),
-            'request': request,
             'template': self,
             'template_description': self.description,
             'template_name': self.name,

src/backend/InvenTree/stock/models.py

@@ -2158,7 +2158,7 @@ class StockItem(
 
     def testResultList(self, **kwargs):
         """Return a list of test-result objects for this StockItem."""
-        return self.testResultMap(**kwargs).values()
+        return list(self.testResultMap(**kwargs).values())
 
     def requiredTestStatus(self):
         """Return the status of the tests required for this StockItem.