testing docs updated

Author: Piyushk8

docs/docs/docs/developer-resources/testing.md

@@ -59,6 +59,64 @@ The `tests/server.ts` file exports the Talawa API server instance that can be im
 
 There aren't any other strict structure requirements for the this directory.
 
+# Mock GraphQL Context Factory Function
+ In Directory `test/MockContext/*`
+
+## **Purpose**  
+The `createMockGraphQLContext` function provides a **fully mocked GraphQL context** for unit and integration testing of GraphQL resolvers. It ensures that resolvers can be tested **without needing a real database, MinIO storage, or authentication service** and works as centralised mocking mechanism.
+
+## **Usage**  
+
+### **Importing the Mock Context**  
+```ts
+import { createMockGraphQLContext } from "test/MockContext/mockGraphQLContext";
+```
+
+### **Creating a Mock Context**  
+#### **For an Unauthenticated User**  
+```ts
+const mockContext = createMockGraphQLContext(false);
+```
+`mockContext.currentClient.isAuthenticated` will be `false`.  
+
+#### **For an Authenticated User**  
+```ts
+const mockContext = createMockGraphQLContext(true, "user123");
+```
+`mockContext.currentClient.user.id` will be `"user123"`.  
+
+---
+
+## **Components in Mock Context**  
+The mock context provides the following:  
+
+| Component       | Description |
+|----------------|------------|
+| `currentClient` | Simulates authenticated/unauthenticated users. |
+| `drizzleClient` | Mocked database client (`createMockDrizzleClient`). |
+| `envConfig` | Mocked environment variables (`API_BASE_URL`). |
+| `jwt.sign` | Mocked JWT generator (`vi.fn()` returning a test token). |
+| `log` | Mocked logger (`createMockLogger`). |
+| `minio` | Mocked MinIO client for object storage (`createMockMinioClient`). |
+| `pubsub` | Mocked pub-sub system for GraphQL subscriptions (`createMockPubSub`). |
+
+---
+
+## **How Contributors Should Use It**  
+
+### **Unit Testing Resolvers** (Mocks dependencies)  
+```ts
+test("should return user data", async () => {
+  const mockContext = createMockGraphQLContext(true, "user123");
+  const result = await userResolver({}, {}, mockContext);
+  expect(result.id).toBe("user123");
+});
+```
+
+## **Key Benefits**  
+**Isolated Testing** – No need for a real database or external services.  
+**Scalable** – Any future changes in `GraphQLContext` can be updated in one place, ensuring a single source of truth.  
+
 ### Future Considerations
 
 In the future there might be a requirement to run some tests sequentially. When that moment arrives separating sequential and parallel tests into separate directories and using separate vitest configuration for them would be the best idea.