PHPUnit assertIsWritable() Function

The assertIsWritable() function is a builtin function in PHPUnit and is used to assert whether the assertiswritable specified that filename is writable or not. This assertion will return true in the case if either given filename exists and is writable else return false. In case of true the asserted test case got passed else test case got failed.

Syntax:

assertIsWritable(string $filename[, string $message = ''])

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

• $filename: This parameter is any type of string that denotes the file name.
• $message: This parameter takes a string value. When the test case got failed this string message got displayed as an error message.

Below examples illustrate the assertIsWritable() function in PHPUnit:

Example 1:

PHP

<?php
use PHPUnit\Framework\TestCase;

class GeeksPhpunitTestCase extends TestCase
{
    public function testNegativeTestcaseForassertIsWritable()
    {
        $filename = "/home/lovely/Documents/php/GeeksPhpunitTestCase";

        // Assert function to test whether given
        // file name is writable or not
        $this->assertIsWritable(
            $filename,
            "filename is writable or Not"
        );
    }
}

?>

Output:

 PHPUnit 8.5.8 by Sebastian Bergmann and contributors.

F                                                                      1 / 1 (100%)

Time: 86 ms, Memory: 10.00 MB

There was 1 failure:

1) GeeksPhpunitTestCase::testNegativeTestcaseForassertIsWritable
filename is writable or Not
Failed asserting that "/home/lovely/Documents/php/GeeksPhpunitTestCase" is writable.

/home/lovely/Documents/php/test.php:16

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

Example 2:

PHP

<?php
use PHPUnit\Framework\TestCase;

class GeeksPhpunitTestCase extends TestCase
{
    public function testPositiveTestcaseForassertIsWritable()
    {
        $filename = "/home/lovely/Documents/php";

        // Assert function to test whether given
        // file name is writable or not
        $this->assertIsWritable(
            $filename,
            "filename is writable or Not"
        );
    }
}

?>

Output:

PHPUnit 8.5.8 by Sebastian Bergmann and contributors.

.                                                 1 / 1 (100%)

Time: 87 ms, Memory: 10.00 MB

OK (1 test, 1 assertion)

Reference:https://phpunit.readthedocs.io/en/9.2/assertions.html#assertiswritable