**Course Title:** Mastering Zend Framework (Laminas): Building Robust Web Applications **Section Title:** Testing and Debugging in Laminas **Topic:** Writing unit tests and integration tests using PHPUnit Welcome to the next topic in our journey of building robust web applications with Laminas! In this section, we'll dive into the world of unit testing and integration testing using PHPUnit. PHPUnit is a powerful testing framework that comes bundled with Laminas, making it an ideal choice for testing our applications. **What are Unit Tests and Integration Tests?** Before we begin, let's define what unit tests and integration tests are: * **Unit tests**: These tests focus on a single unit of code, such as a class, method, or function. The goal is to verify that a small, isolated piece of code behaves as expected in isolation. * **Integration tests**: These tests verify that multiple components work together seamlessly, simulating real-world scenarios. The goal is to ensure that multiple pieces of code interact correctly and informatics data. **Installing PHPUnit and Setup** To get started with PHPUnit, we'll need to install the PHPUnit package via Composer. Open your terminal or command prompt and run the following command: ``` composer require --dev phpunit/phpunit ``` You should see the PHPUnit package installed in the `vendor/phpunit/phpunit` directory. Next, we'll create a basic PHP file to test. Create a new file called `Calculator.php`: ```php // src/Calculator.php namespace Calculator; use Laminas\Db\Adapter\Pdo\Pdo; class Calculator { public function add($a, $b) { return $a + $b; } } ``` **Writing Unit Tests for Calculator Class** Now, let's write some unit tests for the `Calculator` class using PHPUnit. Create a new file called `CalculatorTest.php`: ```php // tests/CalculatorTest.php namespace Calculator\Tests; use Calculator\Calculator; use PHPUnit\Framework\TestCase; class CalculatorTest extends TestCase { public function testAdd() { $calculator = new Calculator(); $result = $calculator->add(2, 3); $this->assertEquals(5, $result); } } ``` In this test, we're creating an instance of the `Calculator` class and calling the `add` method with two arguments. We then verify that the result is equal to 5 using the `assertEquals` method. **Running Unit Tests** To run the unit tests, use the following command: ``` ./vendor/bin/phpunit tests ``` You should see the test run successfully, and the `vmTest result` output indicate that the test passed. **Writing Integration Tests** Integration tests verify that multiple components work together seamlessly. Let's write an integration test that uses the `Calculator` class with a MySQL database using the Laminas Db adapter. ```php // src/IntegrationTest.php namespace Calculator<Integration; use Calculator\Calculator; use Laminas\Db\Adapter\Pdo\Pdo; use Laminas\Db\TableGateway\TableGateway; use Laminas/UIKit; class IntegrationTest extends TestCase { protected $db; protected function setUp() { $this->db = TableGateway:: TableGateway::create( 'calculator', [ 'table' => 'calculators', ] ); } public function testAdd() { $calculator = new Calculator(); $this->db->insert([ 'name' => 'Test Calculator', 'result' => $calculator->add(2, 3), ]); $result = $this->db->selectOne([ 'name' => 'Test Calculator' ]); $this->assertEquals(5, $result['result']); } } ``` In this test, we first set up the database table gateway and create a new instance of the `Calculator` class. We then insert a new record into the `calculators` table using the `add` method and verify that the result is correct using the `selectOne` method. **Best Practices for Writing Effective Unit Tests** Before we move on to the next topic on using Laminas Test tools for functional testing, here are some best practices to keep in mind when writing unit tests: * Keep tests independent and focused on a single unit of code. * Use descriptive test names and comments. * Use mocking to isolate dependencies and make tests more efficient. * Use the `setUp` and `tearDown` methods to set up andteardown resources. * Use assertions like `assertEquals` to verify the expected result. **Takeaways** In this topic, we've written unit tests and integration tests for a simple `Calculator` class using PHPUnit. We've covered the basics of unit testing and integration testing, including setting up the database and using the `TableGateway` class for integration tests. Your turn! Can you try writing your own unit tests for a simple class? Leave a comment below if you need help or have questions. Next up, we'll be covering using Laminas Test tools for functional testing.