PHPUnit assertStringMatchesFormat() Function

The assertStringMatchesFormat() function is a builtin function in PHPUnit and is used to assert whether the given string is matched with the format  or not. This assertion will return true in the case if the given string matched with the type of format else returns false. In case of true the asserted test case got passed else test case got failed.

Syntax:

assertStringMatchesFormat(string $format, string $string[, string $message = ''])

Parameters: This function accepts three parameters as mentioned above and described below:

•   $format: This parameter is represented preestablish layout for data.
•   $string: This parameter is of any type which represents the string.
•   $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 assertStringMatchesFormat() function in PHPUnit:

Example 1:

PHP

<?php
use PHPUnit\Framework\TestCase;

class GeeksPhpunitTestCase extends TestCase
{
    public function testNegativeTestcaseForassertStringMatchesFormat()
    {
        $format =  "%d";
        $String  =  "hh";

        // Assert function to test whether given
        // string is matched with type of format or not
        $this->assertStringMatchesFormat(
            $format,
            $String,
            " given string is matched with type
              of format or not"
        );
    }
}

?>

Output:

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::testNegativeTestcaseForassertStringMatchesFormat
type of format is matched to given string
Failed asserting that string matches format description.
--- Expected
+++ Actual
@@ @@
-%d
+hh

/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 testPositiveTestcaseForassertStringMatchesFormat()
    {
        $format =  "%d";
        $String  =  "24";

        // Assert function to test whether given
        // string is matched with type of format or not
        $this->assertStringMatchesFormat(
            $format,
            $String,
            " given string is matched with type
              of format or not"
        );
    }
}

?>

Output:

PHPUnit 8.5.8 by Sebastian Bergmann and contributors.

.                                                  1 / 1 (100%)

Time: 89 ms, Memory: 10.00 MB

OK (1 test, 1 assertion)

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