Closes sebastianbergmann#2396

Author: sebastianbergmann

CONTRIBUTING.md

@@ -39,12 +39,10 @@ $ git clone git://github.com/sebastianbergmann/phpunit.git
 $ cd phpunit
 ```
 
-Retrieve PHPUnit's dependencies using [Composer](http://getcomposer.org/):
+Retrieve PHPUnit's dependencies using [Composer](https://getcomposer.org/):
 
 ```bash
-$ wget http://getcomposer.org/composer.phar
-
-$ php composer.phar install
+$ composer install
 ```
 
 The `phpunit` script can be used to invoke the PHPUnit test runner:

phpunit

@@ -39,9 +39,9 @@ unset($file);
 
 if (!defined('PHPUNIT_COMPOSER_INSTALL')) {
     fwrite(STDERR,
-        'You need to set up the project dependencies using the following commands:' . PHP_EOL .
-        'wget http://getcomposer.org/composer.phar' . PHP_EOL .
-        'php composer.phar install' . PHP_EOL
+        'You need to set up the project dependencies using Composer:' . PHP_EOL . PHP_EOL .
+        '    composer install' . PHP_EOL . PHP_EOL .
+        'You can learn all about Composer on https://getcomposer.org/.' . PHP_EOL
     );
 
     die(1);