silverstripe-frameworktest/code/TestTagFieldPage.php

<?php
class TestTagFieldPage extends Page {
	
	static $db = array(
		'TestTagString' => 'Text',
		'FixedTags' => 'Text'
	);
	
	static $many_many = array(
		'TestTags' => 'TestTag',
	);
	
	function getCMSFields() {
		$fields = parent::getCMSFields();
		
		$tf1 = new TagField('TestTagString', "Single column tags (try 'one', 'two', 'three', 'four')", 'TestTag');
		$fields->addFieldToTab('Root.Content.Main', $tf1);
		
		$tf2 = new TagField('TestTags', "Relation tags (try 'one', 'two', 'three', 'four')", null, 'TestTag');
		$fields->addFieldToTab('Root.Content.Main', $tf2);
		
		$tf3 = new TagField('FixedTags', "Fixed tags (try 'PHP', 'Ruby', 'Python')", null, 'TestTag');
		$tf3->setCustomTags(array('PHP', 'Ruby', 'Python'));
		$fields->addFieldToTab('Root.Content.Main', $tf3);
		
		return $fields;
	}
	
	function requireDefaultRecords(){
		$class = $this->class;
		if(!DataObject::get_one($class)) {
			$page = new $class();
			$page->Title = "Test TagField";
			$page->write();
		}
	}
	
}