Added readme

Author: Nyholm

Readme.md

@@ -1,13 +1,20 @@
 # Symfony Bundle Test
 
-[![Latest Version](https://img.shields.io/github/release/nyholm/symfony-bundle-test.svg?style=flat-square)](https://github.com/nyholm/symfony-bundle-test/releases)
-[![Build Status](https://img.shields.io/travis/nyholm/symfony-bundle-test.svg?style=flat-square)](https://travis-ci.org/nyholm/symfony-bundle-test)
-[![Code Coverage](https://img.shields.io/scrutinizer/coverage/g/nyholm/symfony-bundle-test.svg?style=flat-square)](https://scrutinizer-ci.com/g/nyholm/symfony-bundle-test)
-[![Quality Score](https://img.shields.io/scrutinizer/g/nyholm/symfony-bundle-test.svg?style=flat-square)](https://scrutinizer-ci.com/g/nyholm/symfony-bundle-test)
+[![Latest Version](https://img.shields.io/github/release/Nyholm/symfony-bundle-test.svg?style=flat-square)](https://github.com/Nyholm/symfony-bundle-test/releases)
+[![Build Status](https://img.shields.io/travis/Nyholm/symfony-bundle-test.svg?style=flat-square)](https://travis-ci.org/Nyholm/symfony-bundle-test)
+[![Code Coverage](https://img.shields.io/scrutinizer/coverage/g/Nyholm/symfony-bundle-test.svg?style=flat-square)](https://scrutinizer-ci.com/g/Nyholm/symfony-bundle-test)
+[![Quality Score](https://img.shields.io/scrutinizer/g/Nyholm/symfony-bundle-test.svg?style=flat-square)](https://scrutinizer-ci.com/g/Nyholm/symfony-bundle-test)
 [![Total Downloads](https://img.shields.io/packagist/dt/nyholm/symfony-bundle-test.svg?style=flat-square)](https://packagist.org/packages/nyholm/symfony-bundle-test)
 
 **Test if your bundle is compatible with different Symfony versions**
 
+When you want to make sure that your bundle works with different versions of Symfony
+you need to create a custom `AppKernel` and load your bundle and configuration. 
+
+Using this bundle test together with Matthias Nobacks's 
+[SymfonyDependencyInjectionTest](https://github.com/matthiasnoback/SymfonyDependencyInjectionTest)
+will give you a good base for testing a Symfony bundle. 
+
 ## Install
 
 Via Composer
@@ -16,4 +23,86 @@ Via Composer
 $ composer require nyholm/symfony-bundle-test
 ```
 
-https://github.com/matthiasnoback/SymfonyDependencyInjectionTest
+## Write a test
+
+```php
+
+use Nyholm\BundleTest\BaseBundleTestCase;
+use Acme\AcmeFooBundle;
+use Acme\Service\Foo;
+
+class BundleInitializationTest extends BaseBundleTestCase
+{
+    protected function getBundleClass()
+    {
+        return AcmeFooBundle::class;
+    }
+
+    public function testInitBundle()
+    {
+        // Boot the kernel.
+        $this->bootKernel();
+        
+        // Get the containter
+        $container = $this->getContainer();
+
+        // Test if you services exists
+        $this->assertTrue($container->has('acme.foo'));
+        $service = $container->get('acme.foo');
+        $this->assertInstanceOf(Foo::class, $service);
+    }
+    
+    public function testBundleWithDifferentConfiguration()
+    {
+        // Create a new Kernel
+        $kernel = $this->createKernel();
+        
+        // Add some configuration
+        $kernel->addConfigFile(__DIR__.'/config.yml');
+        
+        // Add some other bundles we depend on
+        $kernel->addBundle(OtherBundle::class);
+
+        // Boot the kernel as normal ...
+        $this->bootKernel();
+        
+        // ... 
+    }
+}
+
+```
+
+## Configure travis
+
+You want travis to run the highest version of Symfony you support and the lowest
+version. Same with PHP version. There is no need for testing for version in between
+because both Symfony and PHP follow Semver. 
+
+```yaml
+language: php
+
+php:
+    - 5.5
+    - 7.1
+    - hhvm
+env:
+  global:
+    - TEST_COMMAND="vendor/bin/phpunit"
+  matrix:
+    - SYMFONY_VERSION=3.2.*    
+    - SYMFONY_VERSION=2.7.*
+
+matrix:
+  fast_finish: true
+  include:
+    - php: 5.5
+      env: COMPOSER_FLAGS="--prefer-stable --prefer-lowest" SYMFONY_VERSION=2.7.* TEST_COMMAND="vendor/bin/phpunit --coverage-text --coverage-clover=build/coverage.xml"
+
+install:
+    - composer require symfony/symfony:${SYMFONY_VERSION} --no-update
+    - travis_retry composer update ${COMPOSER_FLAGS} --prefer-dist --no-interaction
+
+script:
+    - $TEST_COMMAND
+```
+