Short-circuit the custom migration if there are no SupplierPart objects

- This allows the unit testing to run!

(cherry picked from commit f243b567fd)

InvenTree/InvenTree/status_codes.py

@@ -15,8 +15,6 @@ class StatusCode:
         Render the value as a label.
         """
 
-        print("Rendering:", key, cls.options)
-
         # If the key cannot be found, pass it back
         if key not in cls.options.keys():
             return key

InvenTree/company/migrations/0019_auto_20200413_0642.py

@@ -21,6 +21,12 @@ def reverse_association(apps, schema_editor):
     into the 'manufacturer_name' field.
     """
 
+    # Exit if there are no SupplierPart objects
+    # This crucial otherwise the unit test suite fails!
+    if SupplierPart.objects.count() == 0:
+        print("No SupplierPart objects - skipping")
+        return
+
     print("Reversing migration for manufacturer association")
 
     try:
@@ -49,6 +55,12 @@ def associate_manufacturers(apps, schema_editor):
     It uses fuzzy pattern matching to help the user out as much as possible.
     """
 
+    # Exit if there are no SupplierPart objects
+    # This crucial otherwise the unit test suite fails!
+    if SupplierPart.objects.count() == 0:
+        print("No SupplierPart objects - skipping")
+        return
+
     # Link a 'manufacturer_name' to a 'Company'
     links = {}