given:
        manager.addListener(fooListener1)
        manager.addListener(fooListener2)

        // get the broadcaster and then add more listeners (because broadcasters
        // are cached and so must be maintained correctly after getting defined
        def broadcaster = manager.getBroadcaster(TestFooListener.class)

        manager.addListener(fooListener3)

        when:

    future.addListener(before, directExecutor());
    future.addListener(bad, directExecutor());
    future.addListener(after, directExecutor());

    future.set(1); // BadRunnableException must not propagate.

    before.assertRun();
    after.assertRun();
  }

  public void testNullListener() {
    try {
      future.addListener(null, directExecutor());
      fail();

    future.addListener(before, directExecutor());
    future.addListener(bad, directExecutor());
    future.addListener(after, directExecutor());

    future.set(1); // BadRunnableException must not propagate.

    before.assertRun();
    after.assertRun();
  }

  public void testNullListener() {
    try {
      future.addListener(null, directExecutor());
      fail();

                    println 'gradle.addListener(ComboListener) from $source'
                }
                void settingsEvaluated(Settings settings) {
                    println 'gradle.addListener(ComboListener) from $source'
                }
                void projectsLoaded(Gradle gradle) {
                    println 'gradle.addListener(ComboListener) from $source'
                }

        when:
        daemonScanInfo.notifyOnUnhealthy(notifyAction)

        then:
        1 * listenerManager.addListener({ it instanceof DaemonExpirationListener }) >> { DaemonExpirationListener listener ->
            daemonExpirationListener = listener
        }
        1 * listenerManager.addListener({ it instanceof BuildListener }) >> { BuildListener listener ->
            buildListener = listener
        }

        when:

            holders.remove(holder);
        }
    }

    @Override
    public void addListener(JvmMemoryStatusListener listener) {
        listenerManager.addListener(listener);
    }

    @Override
    public void addListener(OsMemoryStatusListener listener) {
        listenerManager.addListener(listener);
    }

    @Override
    public void removeListener(JvmMemoryStatusListener listener) {

import org.gradle.internal.service.scopes.Scope;
import org.gradle.internal.service.scopes.ServiceScope;

@ServiceScope(Scope.Global.class)
public interface MemoryManager {

    void addListener(JvmMemoryStatusListener listener);

    void addListener(OsMemoryStatusListener listener);

    void removeListener(JvmMemoryStatusListener listener);

    void removeListener(OsMemoryStatusListener listener);

    /**

        buildListenerBroadcast.add("buildFinished", action);
    }

    @Override
    public void addListener(Object listener) {
        addListener("Gradle.addListener", listener);
    }

    @Override
    public void removeListener(Object listener) {
        // do same decoration as in addListener to remove correctly
        getListenerManager().removeListener(decorateUnknownListener(null, listener));
    }

     *
     * @param listener The listener to add.
     */
    public void addTestListener(TestListener listener) {
        testListenerSubscriptions.addListener(listener);
    }

    private void addDispatchAsTestListener(String methodName, Closure closure) {

    }

    def "does nothing when function does nothing"() {
        def listener = Mock(BuildTreeLifecycleListener)
        def action = Mock(Function)

        given:
        listenerManager.addListener(listener)

        when:
        state.run(action)

        then:
        1 * action.apply(_)
        0 * actionExecutor._
        0 * listener._
    }