PHP PHPUnit assertNull()用法及代碼示例

assertNull()函數是PHPUnit中的內置函數，用於斷言變量是否為Null。如果變量為Null，則此斷言將返回true，否則返回false。如果為真，則通過斷言的測試用例，否則測試用例失敗。

用法:

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

參數：此函數接受上述和以下描述的兩個參數：

• $Variable:此參數代表任何類型的變量。
• $message:此參數采用字符串值。當測試用例失敗時，此字符串消息將顯示為錯誤消息。

以下示例說明了PHPUnit中的assertNull()函數：

範例1：

<?php  
use PHPUnit\Framework\TestCase;  
    
class GeeksPhpunitTestCase extends TestCase  
{  
    public function testNegativeTestcaseForassertNull()  
    {  
        $variable = "Null";  
    
        // Assert function to test whether given  
        // variable is Null or not  
        $this->assertNull(  
            $variable,  
            "variable is null or not"
        );  
    }  
}  
    
?> 

輸出：

PHPUnit 8.5.8 by Sebastian Bergmann and contributors.

F                                                  1 / 1 (100%)

Time:88 ms, Memory:10.00 MB

There was 1 failure:

1) GeeksPhpunitTestCase::testPositiveTestcaseForassertNull
variable is null or not
Failed asserting that 'Null' is null.

/home/lovely/Documents/php/test.php:15

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

範例2：

<?php  
use PHPUnit\Framework\TestCase;  
    
class GeeksPhpunitTestCase extends TestCase  
{  
    public function testPositiveTestcaseForassertNull()  
    {  
        $variable = Null;  
    
        // Assert function to test whether given  
        // variable is Null or not  
        $this->assertNull(  
            $variable,  
            "variable is null or not"
        );  
    }  
}  
    
?> 

輸出：

PHPUnit 8.5.8 by Sebastian Bergmann and contributors.

.                                                 1 / 1 (100%)

Time:88 ms, Memory:10.00 MB

OK (1 test, 1 assertion)

參考：https://phpunit.readthedocs.io/en/9.2/assertions.html#assertnull