PHPunit | assertEmpty() Function

The assertEmpty() function is a builtin function in PHPUnit and is used to assert whether the data holder specified is empty or not. This assertion will return true in the case if the data holder provided is empty else return false. In case of true the asserted test case got passed else test case got failed.

Syntax:

assertEmpty( mixed $dataHolder, string $message = '' )

Parameters: This function accepts two parameters as shown in the above syntax. The parameters are described below:

• $dataHolder: This parameter is of any type which represent the data holder to be asserted.
• $message: This parameter takes string value. When the testcase got failed this string message got displayed as error message.

Below programs illustrate the assertEmpty() function in PHPUnit:

Program 1:

<?php
use PHPUnit\Framework\TestCase;

class GeeksPhpunitTestCase extends TestCase
{
    public function testNegativeTestcaseForAssertEmpty()
    {
        $dataHolder = 'test data';

        // Assert function to test whether given
        // data holder (variable) is empty or not
        $this->assertEmpty(
            $dataHolder,
            "data holder is not empty"
        );
    }
}

?>

Output:

PHPUnit 8.2.5 by Sebastian Bergmann and contributors.

F                                                                   1 / 1 (100%)

Time: 69 ms, Memory: 10.00 MB

There was 1 failure:

1) GeeksPhpunitTestCase::testNegativeTestcaseForAssertEmpty
data holder is not empty
Failed asserting that a string is empty.

/home/shivam/Documents/geeks/phpunit/abc.php:13

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

Program 2:

<?php
use PHPUnit\Framework\TestCase;

class GeeksPhpunitTestCase extends TestCase
{
    public function testPositiveTestcaseForAssertEmpty()
    {
        $dataHolder = '';

        // Assert function to test whether given
        // data holder (variable) is empty or not
        $this->assertEmpty(
            $dataHolder,
            "data holder is not empty"
        );
    }
}

?>

Output:

PHPUnit 8.2.5 by Sebastian Bergmann and contributors.

.                                                                   1 / 1 (100%)

Time: 67 ms, Memory: 10.00 MB

OK (1 test, 1 assertion)

Note: To run testcases with phpunit follow steps from here. Also, assertEmpty() is supported by phpunit 7 and above.