PHPUnit Manual

When you are writing tests for existing code, you have to write the same code fragments such as

public function testMethod()
{
}

over and over again. PHPUnit can help you by analyzing the code of the existing class and generating a skeleton test case class for it.

<?php
class Calculator
{
    public function add($a, $b)
    {
        return $a + $b;
    }
}
?>

The following example shows how to generate a skeleton test class for a class named Calculator (see Example 17.1).

phpunit --skeleton-test Calculator
PHPUnit 3.4.14 by Sebastian Bergmann.

Wrote test class skeleton for Calculator to CalculatorTest.php.

For each method in the original class, there will be an incomplete test case (see Chapter 10) in the generated test case class.

phpunit --skeleton-test "Foo\Bar" Bar.php

Below is the output of running the generated test case class.

phpunit --verbose CalculatorTest
PHPUnit 3.4.14 by Sebastian Bergmann.

CalculatorTest
I


Time: 0 seconds

There was 1 incomplete test:

1) testAdd(CalculatorTest)
This test has not been implemented yet.
/home/sb/CalculatorTest.php:54

OK, but incomplete or skipped tests!
Tests: 1, Assertions: 0, Incomplete: 1.

You can use @assert annotation in the documentation block of a method to automatically generate simple, yet meaningful tests instead of incomplete test cases. Example 17.2 shows an example.

<?php
class Calculator
{
    /**
     * @assert (0, 0) == 0
     * @assert (0, 1) == 1
     * @assert (1, 0) == 1
     * @assert (1, 1) == 2
     */
    public function add($a, $b)
    {
        return $a + $b;
    }
}
?>

Each method in the original class is checked for @assert annotations. These are transformed into test code such as

    /**
     * Generated from @assert (0, 0) == 0.
     */
    public function testAdd() {
        $o = new Calculator;
        $this->assertEquals(0, $o->add(0, 0));
    }

Below is the output of running the generated test case class.

phpunit CalculatorTest
PHPUnit 3.4.14 by Sebastian Bergmann.

....

Time: 0 seconds


OK (4 tests, 4 assertions)

Table 17.1 shows the supported variations of the @assert annotation and how they are transformed into test code.

When you are doing Test-Driven Development (see Chapter 13) and write your tests before the code that the tests exercise, PHPUnit can help you generate class skeletons from test case classes.

Following the convention that the tests for a class Unit are written in a class named UnitTest, the test case class' source is searched for variables that reference objects of the Unit class and analyzing what methods are called on these objects. For example, take a look at Example 17.4 which has been generated based on the analysis of Example 17.3.

<?php
class BowlingGameTest extends PHPUnit_Framework_TestCase
{
    protected $game;
 
    protected function setUp()
    {
        $this->game = new BowlingGame;
    }
 
    protected function rollMany($n, $pins)
    {
        for ($i = 0; $i < $n; $i++) {
            $this->game->roll($pins);
        }
    }
 
    public function testScoreForGutterGameIs0()
    {
        $this->rollMany(20, 0);
        $this->assertEquals(0, $this->game->score());
    }
}
?>

<?php
/**
 * Generated by PHPUnit on 2008-03-10 at 17:18:33.
 */
class BowlingGame
{
    /**
     * @todo Implement roll().
     */
    public function roll()
    {
        // Remove the following line when you implement this method.
        throw new RuntimeException('Not yet implemented.');
    }
 
    /**
     * @todo Implement score().
     */
    public function score()
    {
        // Remove the following line when you implement this method.
        throw new RuntimeException('Not yet implemented.');
    }
}
?>