@Test
public void testSubjectVar() {

	builder.addPrefix("", "http://example/")
			.addWhere("?s", ":P", ":O");
	String query = builder.buildString();
	assertContainsRegex(WHERE + OPEN_CURLY + var("s") + SPACE + ":P"
			+ SPACE + ":O" + OPT_SPACE + CLOSE_CURLY, query);
}