Adds a JavaScript library to the page and alters it.
function testLibraryAlter() {
// Verify that common_test altered the title of Farbtastic.
$library = drupal_get_library('system', 'farbtastic');
$this
->assertEqual($library['title'], 'Farbtastic: Altered Library', 'Registered libraries were altered.');
// common_test_library_alter() also added a dependency on jQuery Form.
drupal_add_library('system', 'farbtastic');
$scripts = drupal_get_js();
$this
->assertTrue(strpos($scripts, 'misc/jquery.form.js'), 'Altered library dependencies are added to the page.');
}