Unit tests in Laravel - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a basic unit test class in Laravel.

Laravel

<?php

namespace Tests\Unit;

use PHPUnit\Framework\TestCase;

class ExampleTest extends TestCase
{
    public function testBasicTest()
    {
        $this->assertTrue([1]);
    }
}

Drag options to blanks, or click blank then click option'

ATrue

Btrue

C1

Dfalse

Attempts:

3 left

💡 Hint

Common Mistakes

Using uppercase True instead of lowercase true.

Passing false or 1 instead of true.

The assertTrue method expects a boolean true value to pass the test.

2fill in blank

medium

Complete the code to run a test that checks if two values are equal.

Laravel

public function testValuesAreEqual()
{
    $expected = 5;
    $actual = 2 + 3;
    $this->assert[1]($expected, $actual);
}

Drag options to blanks, or click blank then click option'

ASame

BEqual

CEquals

DEqualTo

Attempts:

3 left

💡 Hint

Common Mistakes

Using assertEqual which does not exist.

Using assertSame which is stricter than needed.

The correct PHPUnit assertion method to check equality is assertEquals.

3fill in blank

hard

Fix the error in the test method to correctly check if a string contains a substring.

Laravel

public function testStringContains()
{
    $string = 'Laravel Framework';
    $this->assertStringContainsString([1], $string);
}

Drag options to blanks, or click blank then click option'

A'framework'

B'Framework'

C'laravel'

D'Laravel'

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase 'framework' which does not match the case.

Using lowercase 'laravel' instead of 'Laravel'.

The substring check is case-sensitive. The string contains 'Laravel' with uppercase L, so the exact case must be used.

4fill in blank

hard

Fill both blanks to create a test that expects an exception to be thrown.

Laravel

public function testException()
{
    $this->expectException([1]::class);
    throw new [2]();
}

Drag options to blanks, or click blank then click option'

A\InvalidArgumentException

B\Exception

C\RuntimeException

D\LogicException

Attempts:

3 left

💡 Hint

Common Mistakes

Using different exception classes in the expect and throw statements.

Omitting the leading backslash in the class name.

The test expects an InvalidArgumentException to be thrown, so both places must use the same exception class.

5fill in blank

hard

Fill all three blanks to write a test that mocks a class method and asserts it was called once.

Laravel

public function testMockMethodCall()
{
    $mock = $this->createMock([1]::class);
    $mock->expects($this->once())
         ->method([2])
         ->willReturn([3]);
    
    $result = $mock->process();
    $this->assertEquals('done', $result);
}

Drag options to blanks, or click blank then click option'

AApp\Services\Processor

B'process'

C'done'

DApp\Models\User

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong class names for mocking.

Passing method name without quotes.

Returning a value that does not match the assertion.

The test mocks the Processor class, expects the process method to be called once, and returns 'done'.

Practice

1. What is the main purpose of unit tests in Laravel?

easy

A. To deploy the application to production

B. To create database migrations

C. To check small parts of code to catch errors early

D. To style the user interface

Solution

1. Step 1: Understand unit test purpose

   Unit tests focus on testing small, isolated parts of code to find bugs early.

2. Step 2: Compare options with unit test goals

   Only To check small parts of code to catch errors early describes this purpose; others relate to deployment, database, or UI.

3. Final Answer:

   To check small parts of code to catch errors early -> Option C

4. Quick Check:

   Unit tests = catch errors early [OK]

Hint: Unit tests check small code parts for bugs early [OK]

Common Mistakes:

• Confusing unit tests with deployment tasks
• Thinking unit tests handle UI styling
• Mixing unit tests with database migrations

2. Which of the following is the correct way to define a test method in a Laravel unit test class?

easy

A. function exampleTest() {}

B. public function testExample() {}

C. public test function example() {}

D. def test_example():

Solution

1. Step 1: Recall Laravel test method syntax

   Laravel test methods are public functions starting with 'test' or annotated with @test.

2. Step 2: Check each option's syntax

   public function testExample() {} uses 'public function testExample() {}' which is correct PHP and Laravel style. Others are invalid PHP or wrong syntax.

3. Final Answer:

   public function testExample() {} -> Option B

4. Quick Check:

   Test methods = public function testName() [OK]

Hint: Test methods start with 'test' and are public functions [OK]

Common Mistakes:

• Using wrong function visibility or missing 'public'
• Using Python syntax in PHP tests
• Incorrect function declaration order

3. Given this Laravel test method, what will be the test result?

public function testSum() {
    $a = 2;
    $b = 3;
    $this->assertEquals(5, $a + $b);
}

medium

A. Test throws a syntax error

B. Test fails because 2 + 3 does not equal 5

C. Test is skipped automatically

D. Test passes because 2 + 3 equals 5

Solution

1. Step 1: Evaluate the sum in the test

   Variables $a and $b are 2 and 3, so $a + $b equals 5.

2. Step 2: Check the assertion

   The assertion expects 5 and compares it to $a + $b, which is 5, so it matches and passes.

3. Final Answer:

   Test passes because 2 + 3 equals 5 -> Option D

4. Quick Check:

   2 + 3 = 5 passes assertion [OK]

Hint: Check math in assertEquals carefully [OK]

Common Mistakes:

• Assuming test fails without checking values
• Confusing assertEquals parameter order
• Thinking syntax error without code issues

4. Identify the error in this Laravel unit test method:

public function testUserName() {
    $user = new User();
    $user->name = 'Alice';
    $this->assertEquals('Alice', $user->username);
}

medium

A. Property 'username' does not exist on User model

B. Missing semicolon after new User()

C. assertEquals parameters are reversed

D. Test method name does not start with 'test'

Solution

1. Step 1: Check User model property usage

   The code sets $user->name but asserts $user->username, which likely does not exist.

2. Step 2: Verify syntax and method name

   There is a semicolon after new User(), and method name starts with 'test', so no syntax or naming errors.

3. Final Answer:

   Property 'username' does not exist on User model -> Option A

4. Quick Check:

   Assert property exists before testing [OK]

Hint: Check property names match exactly in tests [OK]

Common Mistakes:

• Assuming assertEquals parameters order causes error
• Overlooking property name mismatch
• Thinking method name is incorrect

5. You want to test a method that returns a list of active users from the database. Which approach best fits Laravel unit testing principles?

hard

A. Mock the User model's active() method and assert it returns expected data

B. Run the actual database query in the test without mocking

C. Test the method by printing results and checking manually

D. Skip testing because database queries are not testable

Solution

1. Step 1: Understand unit test scope

   Unit tests isolate code parts, so database calls should be mocked to avoid external dependencies.

2. Step 2: Evaluate options for best practice

   Mock the User model's active() method and assert it returns expected data mocks the User model's method and asserts expected results, fitting unit test principles. Run the actual database query in the test without mocking uses real DB, which is integration testing. Test the method by printing results and checking manually is manual and not automated. Skip testing because database queries are not testable is incorrect.

3. Final Answer:

   Mock the User model's active() method and assert it returns expected data -> Option A

4. Quick Check:

   Unit tests mock external calls [OK]

Hint: Mock external dependencies in unit tests [OK]

Common Mistakes:

• Running real database queries in unit tests
• Relying on manual output checks
• Skipping tests for database-related methods