Created Project_Stack_Element_Xref Model | API and test cases

Author: Ruchitha12

app/core/admin.py

@@ -18,6 +18,7 @@
 from .models import PracticeArea
 from .models import ProgramArea
 from .models import Project
+from .models import ProjectStackElementXref
 from .models import ProjectStatus
 from .models import ProjectUrl
 from .models import Referrer
@@ -311,3 +312,11 @@ class ProjectUrlAdmin(admin.ModelAdmin):
         "external_id",
         "url",
     )
+
+
+@admin.register(ProjectStackElementXref)
+class ProjectStackElementXrefAdmin(admin.ModelAdmin):
+    list_display = (
+        "project",
+        "stack_element",
+    )

app/core/api/serializers.py

@@ -14,6 +14,7 @@
 from core.models import PracticeArea
 from core.models import ProgramArea
 from core.models import Project
+from core.models import ProjectStackElementXref
 from core.models import ProjectStatus
 from core.models import ProjectUrl
 from core.models import Referrer
@@ -495,3 +496,23 @@ class Meta:
             "url",
         )
         read_only_fields = ("uuid", "created_at", "updated_at")
+
+
+class ProjectStackElementXrefSerializer(serializers.ModelSerializer):
+    project_name = serializers.CharField(source="project.name", read_only=True)
+    stack_element_name = serializers.CharField(
+        source="stack_element.name", read_only=True
+    )
+
+    class Meta:
+        model = ProjectStackElementXref
+        fields = (
+            "uuid",
+            "project",
+            "project_name",
+            "stack_element",
+            "stack_element_name",
+            "created_at",
+            "updated_at",
+        )
+        read_only_fields = ("uuid", "created_at", "updated_at")

app/core/api/urls.py

@@ -13,6 +13,7 @@
 from .views import PermissionTypeViewSet
 from .views import PracticeAreaViewSet
 from .views import ProgramAreaViewSet
+from .views import ProjectStackElementXrefViewSet
 from .views import ProjectStatusViewSet
 from .views import ProjectUrlViewSet
 from .views import ProjectViewSet
@@ -66,6 +67,11 @@
 router.register(
     r"user-status-types", UserStatusTypeViewSet, basename="user-status-type"
 )
+router.register(
+    r"project-stack-elements",
+    ProjectStackElementXrefViewSet,
+    basename="project-stack-element",
+)
 urlpatterns = [
     path("me/", UserProfileAPIView.as_view(), name="my_profile"),
 ]

app/core/api/views.py

@@ -24,6 +24,7 @@
 from ..models import PracticeArea
 from ..models import ProgramArea
 from ..models import Project
+from ..models import ProjectStackElementXref
 from ..models import ProjectStatus
 from ..models import ProjectUrl
 from ..models import Referrer
@@ -50,6 +51,7 @@
 from .serializers import PracticeAreaSerializer
 from .serializers import ProgramAreaSerializer
 from .serializers import ProjectSerializer
+from .serializers import ProjectStackElementXrefSerializer
 from .serializers import ProjectStatusSerializer
 from .serializers import ProjectUrlSerializer
 from .serializers import ReferrerSerializer
@@ -518,3 +520,9 @@ class ProjectUrlViewSet(viewsets.ModelViewSet):
     permission_classes = [IsAuthenticated]
     queryset = ProjectUrl.objects.all()
     serializer_class = ProjectUrlSerializer
+
+
+class ProjectStackElementXrefViewSet(viewsets.ModelViewSet):
+    permission_classes = [IsAuthenticated]
+    queryset = ProjectStackElementXref.objects.all()
+    serializer_class = ProjectStackElementXrefSerializer

app/core/migrations/0041_projectstackelementxref_project_stack_elements_and_more.py

@@ -0,0 +1,37 @@
+# Generated by Django 4.2.16 on 2025-10-21 04:16
+
+from django.db import migrations, models
+import django.db.models.deletion
+import uuid
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('core', '0040_projecturl'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='ProjectStackElementXref',
+            fields=[
+                ('uuid', models.UUIDField(default=uuid.uuid4, editable=False, primary_key=True, serialize=False, unique=True)),
+                ('created_at', models.DateTimeField(auto_now_add=True, verbose_name='Created at')),
+                ('updated_at', models.DateTimeField(auto_now=True, verbose_name='Updated at')),
+                ('project', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='project_stack_elements', to='core.project')),
+                ('stack_element', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='stack_element_projects', to='core.stackelement')),
+            ],
+            options={
+                'db_table': 'project_stack_element_xref',
+            },
+        ),
+        migrations.AddField(
+            model_name='project',
+            name='stack_elements',
+            field=models.ManyToManyField(blank=True, related_name='projects', through='core.ProjectStackElementXref', to='core.stackelement'),
+        ),
+        migrations.AddConstraint(
+            model_name='projectstackelementxref',
+            constraint=models.UniqueConstraint(fields=('project', 'stack_element'), name='unique_project_stack_element'),
+        ),
+    ]

app/core/migrations/max_migration.txt

@@ -1 +1 @@
-0040_projecturl
+0041_projectstackelementxref_project_stack_elements_and_more

app/core/models.py

@@ -198,6 +198,12 @@ class Project(AbstractBaseModel):
         blank=True,
         through="ProjectProgramAreaXref",
     )
+    stack_elements = models.ManyToManyField(
+        "StackElement",
+        through="ProjectStackElementXref",
+        related_name="projects",
+        blank=True,
+    )
 
     def __str__(self):
         return f"{self.name}"
@@ -386,8 +392,6 @@ class StackElementType(AbstractBaseModel):
     name = models.CharField(max_length=255)
     description = models.TextField(blank=True)
 
-    # PK of this model is the ForeignKey for stack_element
-
     def __str__(self):
         return f"{self.name}"
 
@@ -404,9 +408,6 @@ class StackElement(AbstractBaseModel):
     active = models.BooleanField(null=True)
     element_type = models.ForeignKey(StackElementType, on_delete=models.CASCADE)
 
-    # PK of this model is the ForeignKey for project_stack_element_xref
-    # we might be able to use the builtin django many-to-many relation that manages the xref table automatically
-
     class Meta:
         verbose_name_plural = "Stack Elements"
 
@@ -569,3 +570,30 @@ class ProjectUrl(AbstractBaseModel):
 
     def __str__(self):
         return f"{self.name}"
+
+
+class ProjectStackElementXref(AbstractBaseModel):
+    """
+    Cross-reference table joining a project to a stack element.
+    This allows a project to be associated with multiple stack elements and vice versa.
+    """
+
+    project = models.ForeignKey(
+        Project, on_delete=models.CASCADE, related_name="project_stack_elements"
+    )
+    stack_element = models.ForeignKey(
+        StackElement, on_delete=models.CASCADE, related_name="stack_element_projects"
+    )
+
+    class Meta:
+        db_table = "project_stack_element_xref"
+        constraints = [
+            models.UniqueConstraint(
+                fields=["project", "stack_element"], name="unique_project_stack_element"
+            )
+        ]
+
+    def __str__(self):
+        return (
+            f"Project: {self.project.name} -> StackElement: {self.stack_element.name}"
+        )

app/core/tests/conftest.py

@@ -17,6 +17,7 @@
 from ..models import PracticeArea
 from ..models import ProgramArea
 from ..models import Project
+from ..models import ProjectStackElementXref
 from ..models import ProjectStatus
 from ..models import ProjectUrl
 from ..models import Referrer
@@ -381,3 +382,14 @@ def project_url(project, url_type):
         external_id="This is a test external id",
         url="https://test.com",
     )
+
+
+@pytest.fixture
+def project_stack_element_xref(project, stack_element):
+    """
+    Fixture to create and return a ProjectStackElementXref record
+    linking a project and a stack element.
+    """
+    return ProjectStackElementXref.objects.create(
+        project=project, stack_element=stack_element
+    )

app/core/tests/test_api.py

@@ -1,10 +1,13 @@
+from uuid import UUID
+
 import pytest
 from django.urls import reverse
 from rest_framework import status
 
 from core.api.serializers import ProgramAreaSerializer
 from core.api.serializers import UserSerializer
 from core.models import ProgramArea
+from core.models import ProjectStackElementXref
 from core.models import UserPermission
 
 pytestmark = pytest.mark.django_db
@@ -38,6 +41,7 @@
 SOC_MAJOR_URL = reverse("soc-major-list")
 SOC_MINORS_URL = reverse("soc-minor-list")
 URL_TYPE_URL = reverse("url-type-list")
+PROJECT_STACK_ELEMENTS_URL = reverse("project-stack-element-list")
 
 CREATE_USER_PAYLOAD = {
     "username": "TestUserAPI",
@@ -608,3 +612,113 @@ def test_project_url_url_type_relationship(auth_client, url_type, project_url):
 
     # Verify the url_type relationship was set correctly
     assert res.data["url_type"] == url_type.pk
+
+
+def test_create_project_stack_element(auth_client, project, stack_element):
+    payload = {
+        "project": str(project.uuid),
+        "stack_element": str(stack_element.uuid),
+    }
+    res = auth_client.post(PROJECT_STACK_ELEMENTS_URL, payload)
+    assert res.status_code == status.HTTP_201_CREATED
+
+    assert UUID(str(res.data["project"])) == project.uuid
+    assert UUID(str(res.data["stack_element"])) == stack_element.uuid
+
+
+def test_list_project_stack_elements(auth_client, project_stack_element_xref):
+    res = auth_client.get(PROJECT_STACK_ELEMENTS_URL)
+    assert res.status_code == status.HTTP_200_OK
+
+    # One record created via fixture
+    assert len(res.data) == 1
+    assert UUID(str(res.data[0]["project"])) == project_stack_element_xref.project.uuid
+    assert (
+        UUID(str(res.data[0]["stack_element"]))
+        == project_stack_element_xref.stack_element.uuid
+    )
+
+
+def test_retrieve_project_stack_element(auth_client, project_stack_element_xref):
+    url = reverse(
+        "project-stack-element-detail", args=[project_stack_element_xref.uuid]
+    )
+    res = auth_client.get(url)
+
+    assert res.status_code == status.HTTP_200_OK
+    assert UUID(str(res.data["uuid"])) == project_stack_element_xref.uuid
+    assert UUID(str(res.data["project"])) == project_stack_element_xref.project.uuid
+    assert (
+        UUID(str(res.data["stack_element"]))
+        == project_stack_element_xref.stack_element.uuid
+    )
+
+
+def test_delete_project_stack_element(auth_client, project_stack_element_xref):
+    url = reverse(
+        "project-stack-element-detail", args=[project_stack_element_xref.uuid]
+    )
+    res = auth_client.delete(url)
+
+    assert res.status_code == status.HTTP_204_NO_CONTENT
+    assert not ProjectStackElementXref.objects.filter(
+        uuid=project_stack_element_xref.uuid
+    ).exists()
+
+
+def test_prevent_duplicate_project_stack_element(auth_client, project, stack_element):
+    payload = {"project": str(project.uuid), "stack_element": str(stack_element.uuid)}
+
+    # First creation works
+    res1 = auth_client.post(PROJECT_STACK_ELEMENTS_URL, payload)
+    assert res1.status_code == status.HTTP_201_CREATED
+
+    # Second creation should fail due to unique constraint
+    res2 = auth_client.post(PROJECT_STACK_ELEMENTS_URL, payload)
+    assert res2.status_code == status.HTTP_400_BAD_REQUEST
+
+    # Assert error mentions uniqueness
+    assert any("unique" in str(err).lower() for err in res2.data.values())
+
+
+def test_project_stack_element_workflow(auth_client):
+    # Create a StackElementType
+    stack_type_payload = {"name": "Language", "description": "Programming language"}
+    res_type = auth_client.post(reverse("stack-element-type-list"), stack_type_payload)
+    assert res_type.status_code == status.HTTP_201_CREATED
+    stack_type_uuid = UUID(res_type.data["uuid"])
+
+    # Create a StackElement "Python"
+    stack_element_payload = {
+        "name": "Python",
+        "description": "A high-level programming language",
+        "url": "https://www.python.org/",
+        "logo": "https://upload.wikimedia.org/wikipedia/commons/c/c3/Python-logo-notext.svg",
+        "active": True,
+        "element_type": stack_type_uuid,
+    }
+    res_element = auth_client.post(reverse("stack-element-list"), stack_element_payload)
+    assert res_element.status_code == status.HTTP_201_CREATED
+    stack_element_uuid = UUID(res_element.data["uuid"])
+
+    # Create a Project "PeopleDepot"
+    project_payload = {
+        "name": "PeopleDepot",
+        "description": "People management system",
+        "hide": False,
+    }
+    res_project = auth_client.post(reverse("project-list"), project_payload)
+    assert res_project.status_code == status.HTTP_201_CREATED
+    project_uuid = UUID(res_project.data["uuid"])
+
+    # Link Project + StackElement
+    link_payload = {"project": project_uuid, "stack_element": stack_element_uuid}
+    res_link = auth_client.post(reverse("project-stack-element-list"), link_payload)
+    assert res_link.status_code == status.HTTP_201_CREATED
+
+    # Verify link shows up
+    res_list = auth_client.get(reverse("project-stack-element-list"))
+    assert res_list.status_code == status.HTTP_200_OK
+    assert len(res_list.data) == 1
+    assert res_list.data[0]["project"] == project_uuid
+    assert res_list.data[0]["stack_element"] == stack_element_uuid