### Question:
InjectorWrapper { public static InjectorWrapper wrap(Injector injector) { Preconditions.checkNotNull(injector, "Injector cannot be null."); return new InjectorWrapper(injector); } InjectorWrapper(Injector injector); static InjectorWrapper wrap(Injector injector); @SuppressWarnings("unchecked") ImmutableSet<Object> getJerseyComponents(); ImmutableSet<HealthCheck> getHealthChecks(); ImmutableSet<Task> getTasks(); ImmutableSet<Managed> getManaged(); ImmutableSet<Bundle> getBundles(); ImmutableSet<Command> getCommands(); ImmutableSet<Initializer> getInitializers(); ImmutableSet<Configurator> getConfigurators(); ImmutableList<FilterSpec> getFilterSpecs();  }### Answer:
@Test public void build_with_an_injector() { Injector injector = mock(Injector.class); InjectorWrapper.wrap(injector); }
@Test(expected = NullPointerException.class) public void injector_cannot_be_null() { InjectorWrapper.wrap(null); }