How To Cancel Nock Pending Request? Detailed Guide!

How to Cancel Nock Pending Request? When working with testing libraries for HTTP requests in JavaScript, one name stands out: Nock. Nock simplifies mocking HTTP requests, providing developers the ability to simulate server interactions in a controlled environment. However, if you’re dealing with “pending requests” in Nock, you might find yourself asking questions about how they work and how to manage them.

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Before diving into the nitty-gritty of canceling pending requests, let’s take a moment to understand what Nock is and why it’s so widely used in testing scenarios.

The Beauty of Nock in Testing

Imagine you’re building an application that interacts with an API. Every time your app fetches user data, creates resources, or updates records, it sends HTTP requests to a server. Testing such interactions can be challenging, especially when you want consistent and reliable test outcomes. This is where Nock steps in.

Nock intercepts HTTP requests made during testing, allowing you to:

Simulate server responses.
Control and predict request outcomes.
Avoid actual API calls, which can be slow or incur costs.

In essence, Nock acts as a virtual server, ensuring your tests run smoothly without the need for live endpoints.

The Concept of Pending Requests in Nock

Now, let’s address the elephant in the room: What does “pending request” mean in the context of Nock?

Unlike real HTTP clients, where pending requests are actual network calls waiting for responses, Nock works differently. In Nock, “pending requests” refer to mocked requests that have been defined but not yet triggered during testing. These are essentially expectations that your code hasn’t fulfilled yet.

For instance, if you define a mock to intercept a GET request to https://example.com/users but your code never makes that request, it becomes a pending mock.

How to Cancel or Manage Pending Requests in Nock?

The way you handle pending requests in Nock depends on your goals. Do you want to remove all pending mocks? Prevent certain requests from being mocked? Or deal with real HTTP requests in a mixed scenario? Let’s explore these scenarios one by one.

1. Removing Pending Mocks

Sometimes, you define mocks in your tests but realize they aren’t needed, or perhaps your test didn’t execute as expected. In such cases, removing pending mocks ensures a clean testing state.

Methods to Remove Pending Mocks

Using nock.cleanAll()The most common way to remove all defined mocks, including pending ones, is by calling nock.cleanAll(). This is particularly useful when used in an afterEach hook to reset Nock after every test case.
Example:

javascript

const nock = require('nock');

describe(‘API Tests’, () => {
afterEach(() => {
nock.cleanAll(); // Clean up all mocks after each test
});

it(‘should fetch user data’, async () => {
const scope = nock(‘https://example.com’)
.get(‘/users’)
.reply(200, [{ id: 1, name: ‘John Doe’ }]);

// Simulate an HTTP request here
scope.done(); // Verify all mocks were used
});
});
Using scope.pendingMocks()If you want to check which mocks are still pending, you can use the pendingMocks() method. It returns an array of pending mocks for a specific scope.
However, there’s no direct way to remove individual pending mocks using this method. It’s more of a diagnostic tool.

Example:

javascript

const scope = nock('https://example.com') .get('/users') .reply(200, [{ id: 1, name: 'John Doe' }]);console.log(scope.pendingMocks()); // Output: [ ‘GET https://example.com/users’ ]

2. Preventing Requests from Being Mocked

Sometimes, you may want to prevent certain requests from being mocked altogether. Nock provides tools to manage this effectively.

Disable Network Connections:By calling nock.disableNetConnect(), you can ensure that any request without a matching mock will throw an error. This is useful for catching unintentional or forgotten API calls in your tests.
Example:

javascript

nock.disableNetConnect();
Enable Network Connections:If you want to allow real network connections during testing (e.g., for specific scenarios), you can re-enable them with nock.enableNetConnect().
Example:

javascript

nock.enableNetConnect();

3. Handling Real Pending Requests (If Applicable)

In cases where you’re using Nock alongside a real HTTP client, you might encounter actual pending requests. These are requests initiated by your application that haven’t completed yet. Most modern HTTP clients, such as Axios or Fetch, offer ways to abort or cancel these requests.

Canceling Requests in Axios

Practical Example: Combining Nock with Real-World Scenarios

Here’s an end-to-end example to illustrate handling pending requests with Nock in a typical test scenario:

javascript

const nock = require('nock');

const axios = require('axios');

describe(‘API Tests with Pending Requests’, () => {
afterEach(() => {
nock.cleanAll(); // Ensure clean state after each test
});

it(‘should mock an API call successfully’, async () => {
const scope = nock(‘https://example.com’)
.get(‘/users’)
.reply(200, [{ id: 1, name: ‘John Doe’ }]);

const response = await axios.get(‘https://example.com/users’);
expect(response.data).toEqual([{ id: 1, name: ‘John Doe’ }]);

scope.done(); // Verify all mocks were used
});

it(‘should clean up pending mocks after test’, () => {
nock(‘https://example.com’)
.get(‘/users’)
.reply(200, [{ id: 1, name: ‘John Doe’ }]);

// No request is made here; pending mocks will be cleared in afterEach
});
});

Managing pending requests in Nock is less about canceling network activity and more about controlling and cleaning up mocked expectations. Whether you’re removing unnecessary mocks, preventing unintentional requests, or handling real HTTP calls, Nock equips you with the tools to keep your tests reliable and efficient.

By understanding these techniques, you can ensure that your testing environment remains clean, predictable, and free of unnecessary overhead. After all, a well-maintained test suite is the cornerstone of robust and scalable software.