}
public void testLookup() throws Exception {
MDC.put("key", "value");
MDC.put("number", "2");
MDCStrLookup lookup = new MDCStrLookup();
assertEquals("value", lookup.lookup("key"));
assertEquals("2", lookup.lookup("number"));
assertEquals(null, lookup.lookup(null));
assertEquals(null, lookup.lookup(""));
assertEquals(null, lookup.lookup("other"));
}