Refactoring code for modular approach

tests/test_error_handling.py

@@ -0,0 +1,45 @@
+# tests/test_error_handling.py
+import pytest
+
+
+class TestErrorHandling:
+    def test_invalid_json(self, client, auth_headers):
+        """Test handling of invalid JSON"""
+        response = client.post("/api/v1/products",
+                               headers=auth_headers,
+                               data="invalid json")
+
+        assert response.status_code == 422  # Validation error
+
+    def test_missing_required_fields(self, client, auth_headers):
+        """Test handling of missing required fields"""
+        response = client.post("/api/v1/products",
+                               headers=auth_headers,
+                               json={"title": "Test"})  # Missing product_id
+
+        assert response.status_code == 422
+
+    def test_invalid_authentication(self, client):
+        """Test handling of invalid authentication"""
+        response = client.get("/api/v1/products",
+                              headers={"Authorization": "Bearer invalid_token"})
+
+        assert response.status_code == 403
+
+    def test_nonexistent_resource(self, client, auth_headers):
+        """Test handling of nonexistent resource access"""
+        response = client.get("/api/v1/products/NONEXISTENT", headers=auth_headers)
+        assert response.status_code == 404
+
+        response = client.get("/api/v1/shops/NONEXISTENT", headers=auth_headers)
+        assert response.status_code == 404
+
+    def test_duplicate_resource_creation(self, client, auth_headers, test_product):
+        """Test handling of duplicate resource creation"""
+        product_data = {
+            "product_id": test_product.product_id,  # Duplicate ID
+            "title": "Another Product"
+        }
+
+        response = client.post("/api/v1/products", headers=auth_headers, json=product_data)
+        assert response.status_code == 400