Add some unit testing for the new model

InvenTree/stock/migrations/0041_stockitemtestresult_notes.py

@@ -0,0 +1,18 @@
+# Generated by Django 3.0.5 on 2020-05-16 10:14
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('stock', '0040_stockitemtestresult'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='stockitemtestresult',
+            name='notes',
+            field=models.CharField(blank=True, help_text='Test notes', max_length=500, verbose_name='Notes'),
+        ),
+    ]