composer.json

...
	"require": {
		"laravel/framework": "4.1.*"
	},
	...
	"require-dev": {
		"way/generators": "2.*",
		"phpunit/phpunit": "4.*"
	}
...

console

22:13:31 - INFO - Guard is using TerminalTitle to send notifications.
22:13:32 - INFO - Running all tests
PHP Strict Standards:  Declaration of PHPUnit_Extensions_Progress_ResultPrinter::printDefects() should be compatible with PHPUnit_TextUI_ResultPrinter::printDefects(array $defects, $type) in /Users/andrew/.rvm/gems/ruby-2.0.0-p195/gems/guard-phpunit2-0.2.7/lib/guard/phpunit/formatters/PHPUnit-Progress/PHPUnit/Extensions/Progress/ResultPrinter.php on line 14

Strict Standards: Declaration of PHPUnit_Extensions_Progress_ResultPrinter::printDefects() should be compatible with PHPUnit_TextUI_ResultPrinter::printDefects(array $defects, $type) in /Users/andrew/.rvm/gems/ruby-2.0.0-p195/gems/guard-phpunit2-0.2.7/lib/guard/phpunit/formatters/PHPUnit-Progress/PHPUnit/Extensions/Progress/ResultPrinter.php on line 14
.F

Failures:

  1) PracticeTest::testHelloWorld
     Failed asserting that two strings are equal.
       --- Expected
       +++ Actual
       @@ @@
       -'Hello world'
       +'Hello worlds'
     # /project/app/tests/PracticeTest.php:13
     # phar:///usr/local/Cellar/phpunit/4.0.7/libexec/phpunit-4.0.7.phar/phpunit/TextUI/Command.php:179
     # phar:///usr/local/Cellar/phpunit/4.0.7/libexec/phpunit-4.0.7.phar/phpunit/TextUI/Command.php:132

Finished in 83 ms
2 tests, 2 assertions, 1 failures

ExampleTest.php

<?php

class ExampleTest extends TestCase {

	/**
	 * A basic functional test example.
	 *
	 * @return void
	 */
	public function testBasicExample()
	{
		$crawler = $this->client->request('GET', '/');

		$this->assertTrue($this->client->getResponse()->isOk());
	}

}

Gemfile

source 'https://rubygems.org'
ruby '2.0.0'

gem 'guard', '~> 2.6.1'
gem 'guard-phpunit2', '~> 0.2.7'

Guardfile

guard 'phpunit2', :cli => '--colors', :tests_path => 'app/tests' do
  watch(%r{^.+Test\.php$})
end

phpunit.xml

<?xml version="1.0" encoding="UTF-8"?>
<phpunit backupGlobals="false"
         backupStaticAttributes="false"
         bootstrap="bootstrap/autoload.php"
         colors="true"
         convertErrorsToExceptions="true"
         convertNoticesToExceptions="true"
         convertWarningsToExceptions="true"
         processIsolation="false"
         stopOnFailure="false"
         syntaxCheck="false"
>
    <testsuites>
        <testsuite name="Application Test Suite">
            <directory>./app/tests/</directory>
        </testsuite>
    </testsuites>
</phpunit>

PracticeTest.php

<?php

/**
 * Practice Test
 */
class PracticeTest extends PHPUnit_Framework_Testcase
{
  
  public function testHelloWorld()
  {
    $greeting = "Hello world";

    $this->assertEquals($greeting, 'Hello worlds');
  }
}