PHPUnit9.0 断言-assertNull()

assertNull(mixed $variable[, string $message = ''])

PHPUnit9.0 断言集合

当 ​$actual​ 不是 ​null ​时报告错误，错误讯息由 ​$message​ 指定。
​assertNotNull()​ 是与之相反的断言，接受相同的参数。
示例 1.51 assertNull() 的用法

<?php declare(strict_types=1);
use PHPUnit\Framework\TestCase;

final class NullTest extends TestCase
{
    public function testFailure(): void
    {
        $this->assertNull('foo');
    }
}

$ phpunit NotNullTest
PHPUnit latest.0 by Sebastian Bergmann and contributors.

F

Time: 0 seconds, Memory: 5.00Mb

There was 1 failure:

1) NullTest::testFailure
Failed asserting that 'foo' is null.

/home/sb/NotNullTest.php:6

FAILURES!
Tests: 1, Assertions: 1, Failures: 1.