PHP Unit Testing: Best Practices for Test Coverage

PHP unit test coverage best practices include: using PHPUnit's CodeCoverage tool, isolating unit tests, using Mock objects and Stubs, covering all branches and paths, and using automatic generators. Through these best practices, you can improve the quality and reliability of your applications.

PHP Unit Testing: Best Practices for Test Coverage

In software development, test coverage is a measure of testing A measure of suite effectiveness. It represents the percentage of code that is tested. High test coverage helps improve the quality and reliability of your application. Here are some best practices for improving test coverage in PHP unit tests:

Using PHPUnit’s CodeCoverage tool

PHPUnit provides a built-in CodeCoverage tool that can generate tests Files and lines covered during execution. To use it, add the following code to the PHPUnit. method or class. This can be achieved by using the

@dataProvider

annotation or PHPUnit's setUp() and

tearDown()

methods. <pre class='brush:xml;toolbar:false;'>&lt;phpunit backupGlobals=&quot;false&quot; backupStaticAttributes=&quot;false&quot; bootstrap=&quot;vendor/autoload.php&quot; colors=&quot;true&quot; verbose=&quot;true&quot; coverageClover=&quot;coverage.clover&quot;&gt; &lt;/phpunit&gt;</pre>Using Mock Objects and StubsMock objects and Stubs can be used to mock dependencies, thereby isolating unit tests and improving test coverage.

public function dataProvider() {
    return [
        ['input' => 1, 'expected' => 2],
        ['input' => 2, 'expected' => 4]
    ];
}

/**
 * @dataProvider dataProvider
 */
public function testSum(int $input, int $expected) {
    $this->assertEquals($expected, $this->sum($input));
}

Cover all branches and paths

Make sure the tests cover all possible code paths and branches. Use conditional statements, loops, and exception handling to increase the complexity of your tests.

Use automatic generators

Test code can be automatically generated using tools such as PhpMetrics and PHPCS. These tools can analyze code and generate corresponding test cases, thereby improving coverage.

Practical case

Consider the following PHP code:

$calculatorMock = $this->createMock(Calculator::class);
$calculatorMock->expects($this->once())
    ->method('sum')
    ->with(1, 2)
    ->will($this->returnValue(3));

$this->assertEquals(3, $calculator->sum(1, 2));

The following is a unit test covering all code paths:

<?php
class Calculator {
    public function sum(int $a, int $b) {
        if ($a < 0 || $b < 0) {
            throw new InvalidArgumentException('Input should be non-negative.');
        }
        return $a + $b;
    }
}

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