@Test
public void getIdentifierFile() {

	assertEquals(-1, this.xml.getIdentifier(new File("x"))); //$NON-NLS-1$
	assertEquals(2, this.xml.getIdentifier(new File("a.txt"))); //$NON-NLS-1$
	assertEquals(3, this.xml.getIdentifier(new File("b.txt"))); //$NON-NLS-1$
	assertEquals(4, this.xml.getIdentifier(new File("a.jpg"))); //$NON-NLS-1$
}