commit 6e06662e82e0d20921ea06b2cf9ae3cb9996405c
author Edwin Kempin <ekempin@google.com> Wed Oct 09 08:32:19 2019 +0200
committer Edwin Kempin <ekempin@google.com> Wed Oct 09 16:19:47 2019 +0200
tree 4ed93d842dcbe86dfb3a791264f2db97a1a27fb3
parent 903b73cfdb2d65c0daa7e01e1c38afc5227be489

Add helper class to register extensions in acceptance tests

Registering an extension in tests comes with quite some boilerplate
code. E.g. ChangeIT does:

  @Inject private DynamicSet<ChangeIndexedListener> changeIndexedListeners;

  private ChangeIndexedCounter changeIndexedCounter;
  private RegistrationHandle changeIndexedCounterHandle;

  @Before
  public void addChangeIndexedCounter() {
    changeIndexedCounter = new ChangeIndexedCounter();
    changeIndexedCounterHandle = changeIndexedListeners.add("gerrit", changeIndexedCounter);
  }

  @After
  public void removeChangeIndexedCounter() {
    if (changeIndexedCounterHandle != null) {
      changeIndexedCounterHandle.remove();
    }
  }

This registers the ChangeIndexedCounter for all tests in ChangeIT
although only one test is using it.

We could register the extension only for that one test, then we would
have:

  @Inject private DynamicSet<ChangeIndexedListener> changeIndexedListeners;

  @Test
  public void starUnstar() throws Exception {
    ChangeIndexedCounter changeIndexedCounter = new ChangeIndexedCounter();
    RegistrationHandle changeIndexedCounterHandle = changeIndexedListeners.add("gerrit", changeIndexedCounter);
    try {
      ...
    } finally {
      changeIndexedCounterHandle.remove();
    }
  }

With the new ExtensionRegistry class we can write this as:

  @Inject private ExtensionRegistry extensionRegistry;

  @Test
  public void starUnstar() throws Exception {
    ChangeIndexedCounter changeIndexedCounter = new ChangeIndexedCounter();
    try (Registration registration = extensionRegistry.newRegistration().add(changeIndexedCounter)) {
      ...
    }

It's also possible to chain add calls to add multiple extensions with
one registration:

    try (Registration registration = extensionRegistry.newRegistration().add(extension1).add(extension2)) {
      ...
    }

For now only TraceIT is adapted to use the ExtensionRegistry helper
class. TraceIT now registers extensions always in the methods where they
are used. This should improve the readability of the tests.

Due to erasure of generic types at runtime we need one add method per
extension point in ExtensionRegistry.Registration.

Change-Id: I027b4161e3c5365f479586871fa79e2cb1447f82
Signed-off-by: Edwin Kempin <ekempin@google.com>