validate MTN function transfer from manifest app version 1

server/apps/manif/models.py

@@ -1,4 +1,8 @@
+import re
+
+from django.core.exceptions import ValidationError
 from django.db import models
+from django.utils.translation import gettext_lazy as _
 
 
 def draft_mtn():
@@ -7,6 +11,15 @@ def draft_mtn():
     return f"{str(mtn_count).zfill(9)}DFT"
 
 
+def validate_mtn(value):
+    """Validate manifest tracking number format"""
+    if not re.match(r"[0-9]{9}[A-Z]{3}", value):
+        raise ValidationError(
+            _("%(value)s is not in valid MTN format: [0-9]{9}[A-Z]{3}"),
+            params={"value": value},
+        )
+
+
 # Create your models here.
 class Manifest2(models.Model):
     mtn = models.CharField(

server/apps/manif/tests/test_manifest_model.py

@@ -0,0 +1,26 @@
+import re
+from unittest.mock import MagicMock, patch
+
+import pytest
+from django.core.exceptions import ValidationError
+
+from apps.manif.models import draft_mtn, validate_mtn
+
+
+class TestManifestModel:
+    def test_draft_mtn_follow_rcrainfo_pattern_with_dft_suffix(self, mocker):
+        mock = MagicMock()
+        mock.count.return_value = 5
+        with patch("apps.manif.models.Manifest2.objects.all", return_value=mock):
+            result = draft_mtn()
+            assert isinstance(result, str)
+            assert re.match(r"\d{9}DFT", result)
+
+    @pytest.mark.parametrize("mtn", ["123456789ELC", "111111111DFT", "100200300JJK"])
+    def test_mtn_validation_raises_no_error(self, mtn):
+        assert validate_mtn(mtn) is None
+
+    @pytest.mark.parametrize("mtn", ["foo_bar", "111111DFT", "123456789"])
+    def test_mtn_validation_raises_error(self, mtn):
+        with pytest.raises(ValidationError):
+            assert validate_mtn(mtn) is None