@Override public synchronized Call<List<String>> getValues(String key) {
    if (key == null) throw new NullPointerException("key == null");
    if (key.isEmpty()) throw new IllegalArgumentException("key was empty");
    if (!searchEnabled) return Call.emptyList();
    return Call.create(new ArrayList<>(autocompleteTags.get(key)));
  }
Used for testing. Returns all dependency links unconditionally.
zipkin/src/main/java/zipkin2/storage/InMemoryStorage.java