### Question:
StorageContainerManager implements AutoCloseable { public void removeStorageContainer(long groupId) { synchronized (storageContainers) { storageContainers.remove(groupId); } } StorageContainerManager(); @Nullable StorageContainerInfo getStorageContainer(long groupId); boolean replaceStorageContainer(long groupId, StorageContainerInfo groupInfo); void removeStorageContainer(long groupId); @Override void close();  }### Answer:
@Test public void testRemoveStorageContainer() { long groupId = 1234L; long revision = 5678L; StorageContainerInfo sc1 = StorageContainerInfo.of( groupId, revision, endpoint1); assertNull(manager.getStorageContainer(groupId)); assertTrue(manager.replaceStorageContainer(groupId, sc1)); assertTrue(sc1 == manager.getStorageContainer(groupId)); manager.removeStorageContainer(groupId); assertNull(manager.getStorageContainer(groupId)); }