@Test
public void extractPlaceholders_validURI_MixedPlaceholders() {

	List<String> placeholders = URISignatureHandler
			.extractPlaceholders(validURI_3MixedPlaceholders);
	assertNotNull(placeholders);
	assertEquals("Wrong number of placeholders extracted", 3, placeholders
			.size());
	assertEquals("Wrong first placeholder", "sop_id", placeholders.get(0));
	assertEquals("Wrong second placeholder", "cond_id", placeholders.get(1));
	assertEquals("Wrong third placeholder", "unit", placeholders.get(2));
}