silverstripe-framework/docs/en/02_Developer_Guides/06_Testing/00_Unit_Testing.md

title: Unit and Integration Testing
summary: Test models, database logic and your object methods.

# Unit and Integration Testing

A Unit Test is an automated piece of code that invokes a unit of work in the application and then checks the behavior 
to ensure that it works as it should. A simple example would be to test the result of a PHP method.

**mysite/code/Page.php**


```php
    
    use SilverStripe\CMS\Model\SiteTree;

    class Page extends SiteTree
    {
        public static function MyMethod()
        {
            return (1 + 1);
        }
    }
```

**mysite/tests/PageTest.php**


```php
        
    use Page;
    use SilverStripe\Dev\SapphireTest;

    class PageTest extends SapphireTest
    {
        public function testMyMethod()
        {
            $this->assertEquals(2, Page::MyMethod());
        }
    }
```

<div class="info" markdown="1">
Tests for your application should be stored in the `mysite/tests` directory. Test cases for add-ons should be stored in 
the `(modulename)/tests` directory. 

Test case classes should end with `Test` (e.g `PageTest`) and test methods must start with `test` (e.g `testMyMethod`).

Ensure you [import](http://php.net/manual/en/language.namespaces.importing.php#example-252) any classes you need for the test, including `SilverStripe\Dev\SapphireTest` or `SilverStripe\Dev\FunctionalTest`.
</div>

A SilverStripe unit test is created by extending one of two classes, [SapphireTest](api:SilverStripe\Dev\SapphireTest) or [FunctionalTest](api:SilverStripe\Dev\FunctionalTest). 

[SapphireTest](api:SilverStripe\Dev\SapphireTest) is used to test your model logic (such as a `DataObject`), and [FunctionalTest](api:SilverStripe\Dev\FunctionalTest) is used when 
you want to test a `Controller`, `Form` or anything that requires a web page.

<div class="info" markdown="1">
`FunctionalTest` is a subclass of `SapphireTest` so will inherit all of the behaviors. By subclassing `FunctionalTest`
you gain the ability to load and test web pages on the site. 

`SapphireTest` in turn, extends `PHPUnit_Framework_TestCase`. For more information on `PHPUnit_Framework_TestCase` see 
the [PHPUnit](http://www.phpunit.de) documentation. It provides a lot of fundamental concepts that we build on in this 
documentation.
</div>

## Test Databases and Fixtures

SilverStripe tests create their own database when the test starts. New `ss_tmp` databases are created using the same 
connection details you provide for the main website. The new `ss_tmp` database does not copy what is currently in your 
application database. To provide seed data use a [Fixture](fixtures) file.

<div class="alert" markdown="1">
As the test runner will create new databases for the tests to run, the database user should have the appropriate 
permissions to create new databases on your server.
</div>

<div class="notice" markdown="1">
The test database is rebuilt every time one of the test methods is run. Over time, you may have several hundred test 
databases on your machine. To get rid of them, run `sake dev/tasks/CleanupTestDatabasesTask`.
</div>

## Custom PHPUnit Configuration

The `phpunit` executable can be configured by command line arguments or through an XML file. SilverStripe comes with a 
default `phpunit.xml.dist` that you can use as a starting point. Copy the file into `phpunit.xml` and customize to your 
needs.

**phpunit.xml**


```xml

    <phpunit bootstrap="framework/tests/bootstrap.php" colors="true">
        <testsuite name="Default">
            <directory>mysite/tests</directory>
            <directory>cms/tests</directory>
            <directory>framework/tests</directory>
        </testsuite>
        
        <listeners>
            <listener class="SS_TestListener" file="framework/dev/TestListener.php" />
        </listeners>
        
        <groups>
            <exclude>
                <group>sanitychecks</group>
            </exclude>
        </groups>
    </phpunit>
```

### setUp() and tearDown()

In addition to loading data through a [Fixture File](fixtures), a test case may require some additional setup work to be
run before each test method. For this, use the PHPUnit `setUp` and `tearDown` methods. These are run at the start and 
end of each test.


```php
    
    use SilverStripe\Core\Config\Config;
    use SilverStripe\Dev\SapphireTest;

    class PageTest extends SapphireTest
    {
        function setUp()
        {
            parent::setUp();

            // create 100 pages
            for ($i = 0; $i < 100; $i++) {
                $page = new Page(['Title' => "Page $i"]);
                $page->write();
                $page->copyVersionToStage(Versioned::DRAFT, Versioned::LIVE);
            }

            // set custom configuration for the test.
            Config::inst()->update('Foo', 'bar', 'Hello!');
        }

        public function testMyMethod()
        {
            // ..
        }

        public function testMySecondMethod()
        {
            // ..
        }
    }

```

`tearDownAfterClass` and `setUpBeforeClass` can be used to run code just once for the file rather than before and after 
each individual test case. Remember to class the parent method in each method to ensure the core boot-strapping of tests
takes place.


```php
        
    use SilverStripe\Dev\SapphireTest;
    
    class PageTest extends SapphireTest
    {
        public static function setUpBeforeClass()
        {
            parent::setUpBeforeClass();

            // ..
        }

        public static function tearDownAfterClass()
        {
            parent::tearDownAfterClass();

            // ..
        }
    }
```

### Config and Injector Nesting

A powerful feature of both [`Config`](/developer_guides/configuration/configuration/) and [`Injector`](/developer_guides/extending/injector/) is the ability to "nest" them so that you can make changes that can easily be discarded without having to manage previous values.

The testing suite makes use of this to "sandbox" each of the unit tests as well as each suite to prevent leakage between tests.

If you need to make changes to `Config` (or `Injector`) for each test (or the whole suite) you can safely update `Config` (or `Injector`) settings in the `setUp` or `tearDown` functions.

It's important to remember that the `parent::setUp();` functions will need to be called first to ensure the nesting feature works as expected.


```php
    public static function setUpBeforeClass()
    {
        parent::setUpBeforeClass();
        //this will remain for the whole suite and be removed for any other tests
        Config::inst()->update('ClassName', 'var_name', 'var_value');
    }
    
    public function testFeatureDoesAsExpected()
    {
        //this will be reset to 'var_value' at the end of this test function
        Config::inst()->update('ClassName', 'var_name', 'new_var_value');
    }
    
    public function testAnotherFeatureDoesAsExpected()
    {
        Config::inst()->get('ClassName', 'var_name'); // this will be 'var_value'
    }
```

## Related Documentation

* [How to Write a SapphireTest](how_tos/write_a_sapphiretest)
* [How to Write a FunctionalTest](how_tos/write_a_functionaltest)
* [Fixtures](fixtures)

## API Documentation

* [SapphireTest](api:SilverStripe\Dev\SapphireTest)
* [FunctionalTest](api:SilverStripe\Dev\FunctionalTest)