UPDATE

water/tests.py

@@ -1,18 +1,34 @@
 from unittest.mock import patch
 
+from django.core.cache import cache
 from django.contrib.auth import get_user_model
-from django.test import TestCase
+from django.test import TestCase, override_settings
 from django.urls import Resolver404, resolve
 from rest_framework.test import APIRequestFactory, force_authenticate
 
 from external_api_adapter.adapter import AdapterResponse
 from farm_hub.models import FarmHub, FarmType
 
-from .views import WaterNeedPredictionView, WeatherFarmCardView
+from .views import WaterNeedPredictionView, WaterSummaryView, WeatherFarmCardView
 
 
+TEST_CACHES = {
+    "default": {
+        "BACKEND": "django.core.cache.backends.locmem.LocMemCache",
+        "LOCATION": "water-tests",
+    }
+}
+
+TEST_WATER_NEED_PREDICTION_CACHE_TTL = 14400
+
+
+@override_settings(
+    CACHES=TEST_CACHES,
+    WATER_NEED_PREDICTION_CACHE_TTL=TEST_WATER_NEED_PREDICTION_CACHE_TTL,
+)
 class WeatherViewTests(TestCase):
     def setUp(self):
+        cache.clear()
         self.factory = APIRequestFactory()
         self.user = get_user_model().objects.create_user(
             username="farmer",
@@ -73,6 +89,82 @@ class WeatherViewTests(TestCase):
             payload={"farm_uuid": str(self.farm.farm_uuid)},
         )
 
+    @patch("water.views.external_api_request")
+    def test_water_need_prediction_caches_last_four_ai_responses(self, mock_external_api_request):
+        farms = []
+        for index in range(5):
+            farm = FarmHub.objects.create(owner=self.user, farm_type=self.farm_type, name=f"Farm Cache {index}")
+            farms.append(farm)
+
+            mock_external_api_request.return_value = AdapterResponse(
+                status_code=200,
+                data={"data": {"result": {"totalNext7Days": float(index), "unit": "mm"}}},
+            )
+
+            request = self.factory.get(f"/api/water/need-prediction/?farm_uuid={farm.farm_uuid}")
+            response = WaterNeedPredictionView.as_view()(request)
+
+            self.assertEqual(response.status_code, 200)
+
+        cached_items = cache.get(WeatherFarmCardView.WATER_NEED_PREDICTION_CACHE_KEY)
+
+        self.assertEqual(len(cached_items), 4)
+        self.assertEqual(cached_items[0]["totalNext7Days"], 4.0)
+        self.assertEqual(cached_items[-1]["totalNext7Days"], 1.0)
+
+    @patch("water.views.external_api_request")
+    def test_water_need_prediction_returns_cached_response_for_same_farm(self, mock_external_api_request):
+        mock_external_api_request.return_value = AdapterResponse(
+            status_code=200,
+            data={"data": {"result": {"totalNext7Days": 24.6, "unit": "mm"}}},
+        )
+
+        for _ in range(2):
+            request = self.factory.get(f"/api/water/need-prediction/?farm_uuid={self.farm.farm_uuid}")
+            force_authenticate(request, user=self.user)
+            response = WaterNeedPredictionView.as_view()(request)
+
+            self.assertEqual(response.status_code, 200)
+            self.assertEqual(response.data["data"]["farm_uuid"], str(self.farm.farm_uuid))
+
+        cache_key = WeatherFarmCardView._build_water_need_prediction_cache_key(self.user.id, self.farm.farm_uuid)
+        self.assertEqual(cache.get(cache_key)["totalNext7Days"], 24.6)
+        mock_external_api_request.assert_called_once()
+
+    @patch("water.views.cache.set")
+    @patch("water.views.external_api_request")
+    def test_water_need_prediction_uses_env_ttl_for_cache(self, mock_external_api_request, mock_cache_set):
+        mock_external_api_request.return_value = AdapterResponse(
+            status_code=200,
+            data={"data": {"result": {"totalNext7Days": 24.6, "unit": "mm"}}},
+        )
+
+        request = self.factory.get(f"/api/water/need-prediction/?farm_uuid={self.farm.farm_uuid}")
+        force_authenticate(request, user=self.user)
+        response = WaterNeedPredictionView.as_view()(request)
+
+        self.assertEqual(response.status_code, 200)
+        self.assertTrue(
+            any(call.kwargs.get("timeout") == TEST_WATER_NEED_PREDICTION_CACHE_TTL for call in mock_cache_set.call_args_list)
+        )
+
+    def test_water_summary_caches_last_four_responses(self):
+        for index in range(5):
+            farm = FarmHub.objects.create(owner=self.user, farm_type=self.farm_type, name=f"Summary Farm {index}")
+            request = self.factory.get(f"/api/water/summary/?farm_uuid={farm.farm_uuid}")
+            response = WaterSummaryView.as_view()(request)
+
+            self.assertEqual(response.status_code, 200)
+            cached_items = cache.get(WeatherFarmCardView.WATER_SUMMARY_CACHE_KEY)
+            cached_items[0]["farmWeatherCard"]["condition"] = f"Condition {index}"
+            cache.set(WeatherFarmCardView.WATER_SUMMARY_CACHE_KEY, cached_items, timeout=None)
+
+        cached_items = cache.get(WeatherFarmCardView.WATER_SUMMARY_CACHE_KEY)
+
+        self.assertEqual(len(cached_items), 4)
+        self.assertEqual(cached_items[0]["farmWeatherCard"]["condition"], "Condition 4")
+        self.assertEqual(cached_items[-1]["farmWeatherCard"]["condition"], "Condition 1")
+
     def test_weather_view_rejects_foreign_farm_uuid(self):
         request = self.factory.post("/api/weather/farm-card/", {"farm_uuid": str(self.other_farm.farm_uuid)}, format="json")
         force_authenticate(request, user=self.user)