public Map<Endpoint, CompletableFuture<Void>> futures() {
        return futures;
    }
@Test
    public void testAddReadinessFuture() {
        CompletableFuture<Void> foo = new CompletableFuture<>();
        EndpointReadyFutures readyFutures = new EndpointReadyFutures.Builder().
                addReadinessFuture("foo", foo).
                build(Optional.empty(), INFO);
        assertEquals(new HashSet<>(Arrays.asList(EXTERNAL, INTERNAL)),
                readyFutures.futures().keySet());
        assertIncomplete(readyFutures, EXTERNAL, INTERNAL);
        foo.complete(null);
        assertComplete(readyFutures, EXTERNAL, INTERNAL);
    }