Writing tests for CodeIgniter application is a bit difficult.

But I introduce an easier way to use PHPUnit with CodeIgniter 3.0.

Requirements

• CodeIgniter 3.0
• PHP 5.4 or later
• PHPUnit

Setup

Step 1

Install CodeIgniter 3.0.0.

If you like Composer, I recommend to use CodeIgniter Composer Installer.

Step 2

Install CI PHPUnit Test. Download latest version from https://github.com/kenjis/ci-phpunit-test/releases and unzip it. Copy application/tests folder into application folder.

CodeIgniter-3.0.0/
└── application/
    └── tests/

If you like Composer:

$ cd CodeIgniter-3.0.0/
$ composer require kenjis/ci-phpunit-test --dev
$ php vendor/kenjis/ci-phpunit-test/install.php

Step 3

Fix the three paths in tests/Bootstrap.php if you need. If you used CodeIgniter Composer Installer, you don't have to change.

    $system_path = '../../vendor/codeigniter/framework/system';

    $application_folder = '../../application';

    define('FCPATH', realpath(dirname(__FILE__).'/../../public').'/');

If you use CodeIgniter 3.0 default folder structure. You have to change like below:

--- a/application/tests/Bootstrap.php
+++ b/application/tests/Bootstrap.php
@@ -102,7 +102,7 @@ switch (ENVIRONMENT)
  * Include the path if the folder is not in the same directory
  * as this file.
  */
-   $system_path = '../../vendor/codeigniter/framework/system';
+   $system_path = '../../system';

 /*
  *---------------------------------------------------------------
@@ -230,7 +230,7 @@ switch (ENVIRONMENT)
    define('BASEPATH', str_replace('\\', '/', $system_path));

    // Path to the front controller (this file)
-   define('FCPATH', realpath(dirname(__FILE__).'/../../public').'/');
+   define('FCPATH', realpath(dirname(__FILE__).'/../..').'/');

    // Name of the "system folder"
    define('SYSDIR', trim(strrchr(trim(BASEPATH, '/'), '/'), '/'));

Step 4

Install PHPUnit. See https://phpunit.de/manual/4.7/en/installation.html.

Now you're ready to write and run tests.

How to Write Tests

Controllers

tests/controllers/Welcome_test.php

<?php

class Welcome_test extends TestCase
{
    public function test_index()
    {
        $output = $this->request('GET', ['Welcome', 'index']);
        $this->assertContains('<title>Welcome to CodeIgniter</title>', $output);
    }
}

Models

tests/models/Inventory_model_test.php

<?php

class Inventory_model_test extends TestCase
{
    public function setUp()
    {
        $this->resetInstance();
        $this->CI->load->model('shop/Inventory_model');
        $this->obj = $this->CI->Inventory_model;
    }

    public function test_get_category_list()
    {
        $expected = [
            1 => 'Book',
            2 => 'CD',
            3 => 'DVD',
        ];
        $list = $this->obj->get_category_list();
        foreach ($list as $category) {
            $this->assertEquals($expected[$category->id], $category->name);
        }
    }

    public function test_get_category_name()
    {
        $actual = $this->obj->get_category_name(1);
        $expected = 'Book';
        $this->assertEquals($expected, $actual);
    }
}

If you want to know how to write tests more, see https://github.com/kenjis/ci-phpunit-test/blob/master/docs/HowToWriteTests.md.

How to Run Tests

$ cd CodeIgniter-3.0.0/application/tests/
$ phpunit
PHPUnit 4.6.10 by Sebastian Bergmann and contributors.

Configuration read from /.../codeigniter/application/tests/phpunit.xml

...

Time: 635 ms, Memory: 4.50Mb

OK (3 tests, 4 assertions)

Generating code coverage report in Clover XML format ... done

Generating code coverage report in HTML format ... done

To generate coverage report, Xdebug is needed.

Summary

• Installing CI PHPUnit Test is very easy. You don't have to modify CodeIgniter core files.
• You can write controller tests easily using CI PHPUnit Test.
• You could probably write tests for your application with 100% coverage using CI PHPUnit Test.

Related

• Now you can write tests for CodeIgniter 3.0 apps that contains exit() with ci-phpunit-test

References

• CodeIgniter Testing Guide
• https://github.com/kenjis/ci-phpunit-test
• https://phpunit.de/manual/4.7/en/
• http://www.codeigniter.com/user_guide/