How do I run all my PHPUnit tests?

I have script called Script.php and tests for it in Tests/Script.php, but when I run phpunit Tests it does not execute any tests in my test file. How do I run all my tests with phpunit?

PHPUnit 3.3.17, PHP 5.2.6-3ubuntu4.2, latest Ubuntu

Output:

$ phpunit Tests
PHPUnit 3.3.17 by Sebastian Bergmann.
Time: 0 seconds
OK (0 tests, 0 assertions)

And here are my script and test files:

Script.php

<?php  
function returnsTrue() {  
    return TRUE;  
}  
?>

Tests/Script.php

<?php  
require_once 'PHPUnit/Framework.php';  
require_once 'Script.php'  

class TestingOne extends PHPUnit_Framework_TestCase  
{

    public function testTrue()
    {
        $this->assertEquals(TRUE, returnsTrue());
    }

    public function testFalse()
    {
        $this->assertEquals(FALSE, returnsTrue());
    }
}

class TestingTwo extends PHPUnit_Framework_TestCase  
{

    public function testTrue()  
    {  
        $this->assertEquals(TRUE, returnsTrue());  
    }

    public function testFalse()
    {
        $this->assertEquals(FALSE, returnsTrue());
    }
}  
?>

I created following phpunit.xml and now atleast I can do phpunit --configuration phpunit.xml in my root directory to run the tests located in Tests/

<phpunit backupGlobals="false"
         backupStaticAttributes="false"
         syntaxCheck="false">
  <testsuites>
    <testsuite name="Tests">
      <directory suffix=".php">Tests</directory>
    </testsuite>
  </testsuites>
</phpunit>