assertEquals("java.lang.String", new Entry<String, Integer>() {}.keyType().toString());
  }

  private static <K, V> TypeToken<Map<K, V>> mapOf(Class<K> keyType, Class<V> valueType) {
    return new TypeToken<Map<K, V>>() {}.where(new TypeParameter<K>() {}, keyType)
        .where(new TypeParameter<V>() {}, valueType);
  }