assertEquals(0, $compositeOuter->fieldPosition('A'));
		$this->assertEquals(1, $compositeOuter->fieldPosition('B'));
		$this->assertEquals(3, $compositeOuter->fieldPosition('D'));
		
		$this->assertEquals(0, $compositeInner->fieldPosition('C1'));
		$this->assertEquals(1, $compositeInner->fieldPosition('C2'));
		
		$compositeOuter->insertBefore(new TextField('AB'), 'B');
		$this->assertEquals(0, $compositeOuter->fieldPosition('A'));
		$this->assertEquals(1, $compositeOuter->fieldPosition('AB'));
		$this->assertEquals(2, $compositeOuter->fieldPosition('B'));
	}
	
	public function testTag() {
		$div = new CompositeField(
			new TextField('A'),
			new TextField('B')
		);
		$this->assertStringStartsWith('
FieldHolder()));
		$this->assertStringEndsWith('/div>', trim($div->FieldHolder()));
		
		$fieldset = new CompositeField();
		$fieldset->setTag('fieldset');
		$this->assertStringStartsWith('