自定义错误处理程序:此phpunit测试失败.为什么?(PHP7）

我正在学习PHP，同时编写玩具代码来了解我所学习的内容。

这些是我的"错误和异常处理程序"函数。

我的意图是：

• 转换异常中的任何"旧式"PHP错误
• 显示异常
• 在系统日志中记录错误消息

function display_exception($exception)
{
    print_r($exception);
}
function log_error_or_exception($error_type, $error_message, $error_number = null, $file_name = null, $line_number = null)
{
    $text = 'Message: ' . $error_message . ' - ErrorType: ' . $error_type;
    if ($error_number) {
        $text .= ' - Error#: ' . $error_number;
    }
    if ($file_name) {
        $text .= ' -> ' . $file_name;
    }
    if ($line_number) {
        $text .= ':' . $line_number;
    }
    syslog(LOG_ERR, $text);
}

/**
 * This function logs any uncaught exception that has been thrown. 
 * If in the "dev" environment it also displays the Exception
 *
 * @var  Exception $exception
 * @return void
 */
function custom_exception_handler($exception)
{
    if (ENV == 'dev') {
        display_exception($exception);
    }
    log_error_or_exception(get_class($exception), $exception->getMessage(), $exception->getCode(), $exception->getFile(), $exception->getLine());
}
/**
 * This function converts an "old style" PHP Error in an ErrorException
 * 
 * @var  int  $errno
 * @var  string  $errstr
 * @var  string|null  $errfile
 * @var  int|null  $errline
 * @var  array $errcontext
 * @return false|void
 */
function custom_error_handler(int $errno, string $errstr, string $errfile = null, int $errline = null, array $errcontext = array())
{
    // if error_reporting() is false it means that the error was trigger by a line having
    // the error control operator "@" so the error should never be displayed.
    // Sometimes thought it's convenient to log it
    if (!error_reporting()) {
        if (ENV == 'dev') {
            log_error_or_exception('Error', $errstr, $errno, $errfile, $errline);
        }
        return false;
    }
    throw new ErrorException($errstr, $errno, 1, $errfile, $errline);
    echo "this should not be displayed";
}
set_exception_handler('custom_exception_handler');
set_error_handler('custom_error_handler');

现在我有一个对象

<?php
require_once 'app/src/ErrorExceptionHandlers.php';
class Obj
{
    public function method($value){
        $result = preg_match('/@/', $value);
    }
}

如果我运行这个代码，一切都如预期：

define('ENV', 'dev');
$object = new Obj;
$object->method(array());

我得到：

ErrorException Object
(
    [message:protected] => preg_match() expects parameter 2 to be string, array given
    [string:Exception:private] => 
    ...
)

如果我尝试运行这个phpunit测试

<?php
require_once 'app/src/models/obj.php';
define('ENV', 'dev');
class ObjTest extends 'PHPUnit_Framework_TestCase
{
    /**
     * @ExpectedException ErrorException
     */
    public function test_method(){
        $object = new Obj();
        $object->method(array());
    }
}

我得到：

There was 1 error:
1) ObjTest::test_method
ErrorException: preg_match() expects parameter 2 to be string, array given

为什么测试失败？