// Register listeners :
// 1- CountingListener l1
// 2- ThrowingListener bad
// 3- TotalCountingListener l2
// 4- AppendingListener l3
ProvidedServiceListener l1 = new CountingListener();
ps.addListener(l1);
ProvidedServiceListener bad = new ThrowingListener();
ps.addListener(bad);
ProvidedServiceListener l2 = new TotalCountingListener();
ps.addListener(l2);
ProvidedServiceListener l3 = new AppendingListener();
ps.addListener(l3);
// Check initial valued are untouched
assertEquals(0, registrations);
assertEquals(0, unregistrations);