Mocking and faking in Laravel - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is mocking in Laravel testing?

Mocking is creating a fake version of a class or interface to simulate its behavior during tests without using the real implementation.

intermediate

What is the difference between mocking and faking in Laravel?

Mocking simulates specific methods and their responses, while faking replaces entire services or classes with simple implementations for testing.

beginner

How do you create a mock of a class in Laravel?

Use the `mock()` helper or `Mockery::mock()` to create a mock object that you can set expectations on for method calls.

beginner

What is a Laravel fake and when would you use it?

A fake is a simple replacement for a service, like the Mail or Queue, used to test if actions were performed without sending real emails or jobs.

beginner

Why is mocking useful in unit testing?

Mocking isolates the code being tested by replacing dependencies, so tests run faster and focus only on the code's logic.

Which Laravel helper is commonly used to create a mock object?

A fake()

B stub()

C simulate()

D mock()

The mock() helper creates a mock object to simulate class behavior in tests.

What does a Laravel fake typically replace in tests?

A Middleware

B Entire services like Mail or Queue

C Routes

D Database connections

Fakes replace services such as Mail or Queue to prevent real actions during tests.

Why should you use mocking in unit tests?

A To isolate the code and avoid real dependencies

B To slow down tests

C To test the database

D To deploy the app

Mocking isolates the code under test by replacing dependencies with controlled mocks.

Which package does Laravel use internally for mocking?

A Mockery

B PHPUnit Mock

C Faker

D Guzzle

Laravel uses Mockery to create mock objects in tests.

What is the main benefit of faking a service in Laravel tests?

A Change the database schema

B Make the app slower

C Avoid performing real actions like sending emails

D Add new routes

Faking prevents real actions, making tests safe and faster.

Explain how mocking helps in Laravel unit testing and give an example of when to use it.

Think about testing a class that calls an external API.

Describe the difference between mocking and faking in Laravel and why each is useful.

Consider testing mail sending vs. testing a method call.

Practice

1. What is the main purpose of mocking and faking in Laravel testing?

easy

A. To automatically generate user interfaces

B. To simulate external services without performing real actions

C. To permanently store test data in the database

D. To speed up the application in production

Solution

1. Step 1: Understand mocking and faking concept

   Mocking and faking are used to imitate external services or actions during tests without actually performing them.

2. Step 2: Identify the purpose in Laravel testing

   Laravel uses mocking and faking to avoid real side effects like sending emails or making HTTP requests during tests.

3. Final Answer:

   To simulate external services without performing real actions -> Option B

4. Quick Check:

   Mocking = simulate services [OK]

Hint: Mocking means faking external actions in tests [OK]

Common Mistakes:

• Thinking mocking speeds up production
• Confusing mocking with real data storage
• Assuming mocking creates UI automatically

2. Which Laravel method correctly fakes sending emails in a test?

easy

A. Mail::fake();

B. Mail::sendFake();

C. Mail::mock();

D. Mail::simulate();

Solution

1. Step 1: Recall Laravel's mail faking method

   Laravel provides the Mail::fake() method to fake email sending during tests.

2. Step 2: Check method correctness

   Only Mail::fake() is the correct and existing method; others are invalid or do not exist.

3. Final Answer:

   Mail::fake(); -> Option A

4. Quick Check:

   Mail::fake() = correct syntax [OK]

Hint: Use Mail::fake() to fake emails in Laravel tests [OK]

Common Mistakes:

• Using non-existent methods like Mail::sendFake()
• Confusing mock() with fake()
• Forgetting the parentheses ()

3. What will the following Laravel test code output?

use Illuminate\Support\Facades\Http;

Http::fake();

$response = Http::get('https://example.com/api');

return $response->status();

medium

A. null

B. 404

C. 500

D. 200

Solution

1. Step 1: Understand Http::fake() behavior

   Http::fake() fakes all HTTP requests and returns a default successful response with status 200.

2. Step 2: Analyze the returned status code

   The $response->status() returns 200 because the fake response simulates success.

3. Final Answer:

   200 -> Option D

4. Quick Check:

   Http::fake() returns 200 status [OK]

Hint: Http::fake() returns 200 status by default [OK]

Common Mistakes:

• Assuming fake returns 404 or error
• Expecting null instead of response object
• Confusing Http::fake() with real HTTP call

4. Identify the error in this Laravel test code snippet:

use Illuminate\Support\Facades\Storage;

Storage::fake('local');

Storage::put('file.txt', 'Hello');

$this->assertTrue(Storage::exists('file.txt'));

medium

A. Storage::fake() must be called with 'public' disk, not 'local'

B. Storage::exists() should be Storage::disk('local')->exists()

C. No error, the code is correct

D. Storage::put() cannot be used after Storage::fake()

Solution

1. Step 1: Understand Storage::fake() usage

   Storage::fake('local') fakes the 'local' disk, which is Laravel's default disk.

2. Step 2: Check method calls for disk specification

   Storage::put() and Storage::exists() use the default disk ('local'), so they interact with the faked disk correctly. The assertion passes.

3. Final Answer:

   No error, the code is correct -> Option C

4. Quick Check:

   Default disk = 'local' [OK]

Hint: Storage:: methods use default disk after Storage::fake('local') [OK]

Common Mistakes:

• Thinking disk must always be explicitly specified
• Believing Storage::put() is disallowed after fake
• Confusing required disk names

5. You want to test that your Laravel app sends exactly one notification to a user without actually sending it. Which approach correctly achieves this?

hard

A. Use Notification::fake() and then assertNotificationSent()

B. Use Notification::send() and check the database for records

C. Use Notification::mock() and assertNothingSent()

D. Use Notification::fake() and then assertNothingSent()

Solution

1. Step 1: Choose the correct faking method for notifications

   Notification::fake() prevents real notifications from sending and allows assertions.

2. Step 2: Use the right assertion to check one notification sent

   assertNotificationSent() verifies that a notification was sent exactly once to the user.

3. Final Answer:

   Use Notification::fake() and then assertNotificationSent() -> Option A

4. Quick Check:

   Notification::fake() + assertNotificationSent() = test notifications [OK]

Hint: Fake notifications, then assertNotificationSent() to check sends [OK]

Common Mistakes:

• Using assertNothingSent() when expecting a notification
• Trying to check notifications via database records
• Using non-existent Notification::mock() method