Unit tests in Laravel - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What is the output of this Laravel unit test?

Consider this Laravel unit test method. What will be the test result when running it?

Laravel

<?php
public function testUserCreation()
{
    $user = User::factory()->make(['email' => '[e-mail]']);
    $this->assertEquals('[e-mail]', $user->email);
}

A The test fails because the user is not saved to the database.

B The test passes because the email matches the expected value.

C The test throws an error because User::factory() is undefined.

D The test fails because assertEquals is used incorrectly.

💡 Hint

Remember that make() creates an instance without saving it.

The factory's make() method creates a User instance with the given email but does not save it. The assertEquals checks the email property correctly, so the test passes.

📝 Syntax

intermediate

Which option correctly defines a Laravel unit test method?

Identify the correct syntax for a Laravel unit test method inside a test class.

A public function test_example() { $this->assertTrue(true); }

B public testExample() { $this->assertTrue(true); }

C function testExample() { $this->assertTrue(true); }

D public function testExample { $this->assertTrue(true); }

💡 Hint

Test methods must be public functions with parentheses.

In Laravel, test methods must be public functions with parentheses and a valid name. Option A follows this pattern correctly.

🔧 Debug

advanced

Why does this Laravel unit test fail with a database error?

This test tries to create a user and check the database, but it fails with a database error. Why?

Laravel

<?php
public function testUserIsSaved()
{
    $user = User::factory()->make();
    $this->assertDatabaseHas('users', ['email' => $user->email]);
}

A Because the test method is missing a call to refresh the database connection.

B Because assertDatabaseHas requires a saved model instance, make() is invalid here.

C Because the users table does not exist in the test database.

D Because make() does not save the user to the database, so the record is missing.

💡 Hint

Check the difference between make() and create() in Laravel factories.

The make() method creates a model instance without saving it. Therefore, the database does not have the user record, causing assertDatabaseHas to fail.

❓ state_output

advanced

What is the value of $count after this Laravel test runs?

Given this test code, what will be the value of $count after execution?

Laravel

<?php
public function testUserCount()
{
    User::factory()->count(3)->create();
    $count = User::count();
}

A 1

B 0

C 3

D Throws an error because User::count() is not accessible.

💡 Hint

Factories with create() save records to the database.

The factory creates and saves 3 users, so User::count() returns 3.

🧠 Conceptual

expert

Which option best describes the purpose of Laravel's RefreshDatabase trait in unit tests?

What does the RefreshDatabase trait do when used in Laravel unit tests?

A It resets the database by running migrations before each test to ensure a clean state.

B It caches database queries to speed up tests.

C It disables database transactions during tests.

D It automatically seeds the database with test data before each test.

💡 Hint

Think about how to keep tests isolated and avoid leftover data.

RefreshDatabase runs migrations before each test, resetting the database to a clean state to avoid data conflicts between tests.