PHPUnit assert exception method

assertException.php

<?php

// Add this method to your test class

/**
 * Asserts that the given callback throws the given exception.
 *
 * @param string $expectClass The name of the expected exception class
 * @param callable $callback A callback which should throw the exception
 * @param callable|null $onException A function to call after exception check. It may be used to test the exception.
 */
protected function assertException(string $expectClass, callable $callback, callable $onException = null)
{
    try {
        $callback();
    } catch (\Throwable $exception) {
        $this->assertInstanceOf($expectClass, $exception, "The thrown exception is not an instance of $expectClass");
        if ($onException) {
            $onException($exception);
        }
        return;
    }

    $this->fail('No exception has been thrown');
}