How to increase timeout for a single test case in mocha

Adjusting test-level timeout values

Understanding how to modify timeouts is crucial if you have tests that need more time to finish. This allows your test to have ample time for operations like data processing or network responses before it is prematurely marked as a failure.

Tuning specific timeout settings

For tests with varying complexity and execution times, you can fine-tune the timeout settings as follows:

// Because every test deserves to finish its "race".
it('marathon test', function(done) {
  this.timeout(10000); // This test is a marathon, not a sprint. Give it 10 seconds.
  // Complex test code here
  done();
});


But remember, with great power, comes great responsibility. Don't use extended timeouts excessively as it can make your tests slower than a herd of turtles stampeding through peanut butter.

Working with hooks

In Mocha, you can also set custom timeouts using beforeEach, afterEach hooks. Especially when you have setup or teardown operations that need an extended timeout:

beforeEach(function() {
  this.timeout(4000); // Setup that takes "ages" to complete
});


Command line & package.json scripts

For setting a timeout from the command line or within a package.json script, use the --timeout flag:

mocha --timeout 5000 // All tests get a leisurely 5-second timeout


Or within your package.json:

"scripts": {
  "test": "mocha --timeout 5000"
}


Take care here! Arrow functions can cause issues because this within an arrow function does not have the test's context. Furthermore, a global command line timeout can affect all tests, so use it wisely.

Know when to tweak timeouts

You should only extend timeouts when necessary, such as during external API calls, database operations, or file I/O processing. These operations might take longer and need a bit more time to finish without causing premature test failures.

Managing async operations

Asynchronous operations are common in JavaScript, and managing timeouts for those is crucial. You can achieve this by using the done callback or the async/await syntax to ensure your test waits for all asynchronous tasks to wrap up within the defined timeout:

// Because async stuff takes "forever"
it('test that waits for its coffee', async function() {
  this.timeout(7000); // Perks up only after coffee, give it 7 seconds
  await coffeeMakingAsyncFunction();
});


Conducting best practices

Global timeouts are considered a last resort. Adjust only what is needed to maintain the balance between reliability and speed. Keeping an eye on and optimizing your test cases can help manage this balance effectively.