Add comprehensive tests for Parks API and models

- Implemented extensive test cases for the Parks API, covering endpoints for listing, retrieving, creating, updating, and deleting parks.
- Added tests for filtering, searching, and ordering parks in the API.
- Created tests for error handling in the API, including malformed JSON and unsupported methods.
- Developed model tests for Park, ParkArea, Company, and ParkReview models, ensuring validation and constraints are enforced.
- Introduced utility mixins for API and model testing to streamline assertions and enhance test readability.
- Included integration tests to validate complete workflows involving park creation, retrieval, updating, and deletion.

parks/models/areas.py

@@ -9,6 +9,11 @@ from .parks import Park
 
 @pghistory.track()
 class ParkArea(TrackedModel):
+    
+    # Import managers
+    from ..managers import ParkAreaManager
+    
+    objects = ParkAreaManager()
     id: int  # Type hint for Django's automatic id field
     park = models.ForeignKey(Park, on_delete=models.CASCADE, related_name="areas")
     name = models.CharField(max_length=255)

parks/models/companies.py

@@ -1,8 +1,15 @@
 from django.contrib.postgres.fields import ArrayField
 from django.db import models
 from core.models import TrackedModel
+import pghistory
 
+@pghistory.track()
 class Company(TrackedModel):
+    
+    # Import managers
+    from ..managers import CompanyManager
+    
+    objects = CompanyManager()
     class CompanyRole(models.TextChoices):
         OPERATOR = 'OPERATOR', 'Park Operator'
         PROPERTY_OWNER = 'PROPERTY_OWNER', 'Property Owner'

parks/models/parks.py

@@ -17,6 +17,11 @@ if TYPE_CHECKING:
 
 @pghistory.track()
 class Park(TrackedModel):
+    
+    # Import managers
+    from ..managers import ParkManager
+    
+    objects = ParkManager()
     id: int  # Type hint for Django's automatic id field
     STATUS_CHOICES = [
         ("OPERATING", "Operating"),
@@ -81,6 +86,43 @@ class Park(TrackedModel):
 
     class Meta:
         ordering = ["name"]
+        constraints = [
+            # Business rule: Closing date must be after opening date
+            models.CheckConstraint(
+                name="park_closing_after_opening",
+                check=models.Q(closing_date__isnull=True) | models.Q(opening_date__isnull=True) | models.Q(closing_date__gte=models.F("opening_date")),
+                violation_error_message="Closing date must be after opening date"
+            ),
+            # Business rule: Size must be positive
+            models.CheckConstraint(
+                name="park_size_positive",
+                check=models.Q(size_acres__isnull=True) | models.Q(size_acres__gt=0),
+                violation_error_message="Park size must be positive"
+            ),
+            # Business rule: Rating must be between 1 and 10
+            models.CheckConstraint(
+                name="park_rating_range",
+                check=models.Q(average_rating__isnull=True) | (models.Q(average_rating__gte=1) & models.Q(average_rating__lte=10)),
+                violation_error_message="Average rating must be between 1 and 10"
+            ),
+            # Business rule: Counts must be non-negative
+            models.CheckConstraint(
+                name="park_ride_count_non_negative",
+                check=models.Q(ride_count__isnull=True) | models.Q(ride_count__gte=0),
+                violation_error_message="Ride count must be non-negative"
+            ),
+            models.CheckConstraint(
+                name="park_coaster_count_non_negative",
+                check=models.Q(coaster_count__isnull=True) | models.Q(coaster_count__gte=0),
+                violation_error_message="Coaster count must be non-negative"
+            ),
+            # Business rule: Coaster count cannot exceed ride count
+            models.CheckConstraint(
+                name="park_coaster_count_lte_ride_count",
+                check=models.Q(coaster_count__isnull=True) | models.Q(ride_count__isnull=True) | models.Q(coaster_count__lte=models.F("ride_count")),
+                violation_error_message="Coaster count cannot exceed total ride count"
+            ),
+        ]
 
     def __str__(self) -> str:
         return self.name

parks/models/reviews.py

@@ -1,10 +1,16 @@
 from django.db import models
+from django.db.models import functions
 from django.core.validators import MinValueValidator, MaxValueValidator
 from core.history import TrackedModel
 import pghistory
 
 @pghistory.track()
 class ParkReview(TrackedModel):
+    
+    # Import managers  
+    from ..managers import ParkReviewManager
+    
+    objects = ParkReviewManager()
     """
     A review of a park.
     """
@@ -44,6 +50,27 @@ class ParkReview(TrackedModel):
     class Meta:
         ordering = ['-created_at']
         unique_together = ['park', 'user']
+        constraints = [
+            # Business rule: Rating must be between 1 and 10 (database level enforcement)
+            models.CheckConstraint(
+                name="park_review_rating_range",
+                check=models.Q(rating__gte=1) & models.Q(rating__lte=10),
+                violation_error_message="Rating must be between 1 and 10"
+            ),
+            # Business rule: Visit date cannot be in the future
+            models.CheckConstraint(
+                name="park_review_visit_date_not_future",
+                check=models.Q(visit_date__lte=functions.Now()),
+                violation_error_message="Visit date cannot be in the future"
+            ),
+            # Business rule: If moderated, must have moderator and timestamp
+            models.CheckConstraint(
+                name="park_review_moderation_consistency",
+                check=models.Q(moderated_by__isnull=True, moderated_at__isnull=True) | 
+                      models.Q(moderated_by__isnull=False, moderated_at__isnull=False),
+                violation_error_message="Moderated reviews must have both moderator and moderation timestamp"
+            ),
+        ]
 
     def __str__(self):
         return f"Review of {self.park.name} by {self.user.username}"