private void checkString(T instance) {
   assertThat(
       instance.toString(),
       CoreMatchers.startsWith(
           type.getCanonicalName().substring(type.getPackage().getName().length() + 1) + "{"));
   assertThat(instance.toString(), endsWith("}"));
   Class<?> currentType = type;
   do {
     for (Field field : type.getDeclaredFields()) {
       if (!field.isSynthetic()
           && !Modifier.isStatic(field.getModifiers())
           && !ignoredFields.contains(field.getName())) {
         assertThat(instance.toString(), containsString(field.getName()));
       }
     }
   } while ((currentType = currentType.getSuperclass()) != Object.class);
 }