PHP 预言之谜

PHP Prophecy Mystery

$entity_type->isSubClassOf('Drupal\Core\Entity\FieldableEntityInterface')->willReturn(TRUE); 遇到了这个令人费解的错误:

Prophecy\Exception\Call\UnexpectedCallException: Method call:
  - isSubclassOf("Drupal\Core\Entity\FieldableEntityInterface")
on Double\EntityTypeInterface\P121 was not expected, expected calls were:
  - isSubClassOf(exact("Drupal\Core\Entity\FieldableEntityInterface"))

细心的读者会在isSub之后观察小写c与大写c的对比。我将问题发布到 https://github.com/phpspec/prophecy/issues/249