Update "date" field for StockItemTestResult (#11586)

* Update "date" field for StockItemTestResult

- Allow editing of date (via admin)

* Mark 'date' and 'user' as read-only unless importing

* Revert API field name

* Fix default value

* Fix migration

---------

Co-authored-by: Matthias Mair <code@mjmair.com>

src/backend/InvenTree/importer/mixins.py

@@ -24,11 +24,11 @@ class DataImportSerializerMixin:
         Determine if the serializer is being used for data import,
         and if so, adjust the serializer fields accordingly.
         """
-        importing = kwargs.pop('importing', False)
+        self._is_importing = kwargs.pop('importing', False)
 
         super().__init__(*args, **kwargs)
 
-        if importing:
+        if self._is_importing:
             # Exclude any fields which are not able to be imported
             importable_field_names = list(self.get_importable_fields().keys())
             field_names = list(self.fields.keys())

src/backend/InvenTree/stock/migrations/0119_alter_stockitemtestresult_date.py

@@ -0,0 +1,22 @@
+# Generated by Django 5.2.12 on 2026-03-21 08:00
+
+import InvenTree.helpers
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("stock", "0118_auto_20260205_1218"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="stockitemtestresult",
+            name="date",
+            field=models.DateTimeField(
+                default=InvenTree.helpers.current_time,
+                verbose_name="Date"
+            ),
+        ),
+    ]

src/backend/InvenTree/stock/models.py

@@ -3101,4 +3101,6 @@ class StockItemTestResult(InvenTree.models.InvenTreeMetadataModel):
         help_text=_('The timestamp of the test finish'),
     )
 
-    date = models.DateTimeField(auto_now_add=True, editable=False)
+    date = models.DateTimeField(
+        default=InvenTree.helpers.current_time, verbose_name=_('Date')
+    )

src/backend/InvenTree/stock/serializers.py

@@ -220,7 +220,16 @@ class StockItemTestResultSerializer(
             'template',
             'template_detail',
         ]
-        read_only_fields = ['pk', 'user', 'date']
+        read_only_fields = ['pk']
+
+    def __init__(self, *args, **kwargs):
+        """Handle custom initialization for the serializer."""
+        super().__init__(*args, **kwargs)
+
+        if not self._is_importing:
+            # Unless we are importing data, mark the 'user' and 'date' fields as read-only
+            self.fields['user'].read_only = True
+            self.fields['date'].read_only = True
 
     user_detail = enable_filter(
         UserSerializer(source='user', read_only=True, allow_null=True),