PHPUnit | assertStringContainsString() function

assertStringContainsString(string $substring, string $string, string $message = ''])

1. $substring: This parameter represents the string to be substring of given string.
2. $string: This parameter is string for which the assert function will check whether it contains substring or not.
3. $message: This parameter takes string value. When the testcase got failed this string message got displayed as error message.

<?php
use PHPUnit\Framework\TestCase;

class GeeksPhpunitTestCase extends TestCase
{
    public function testNegativeTestcaseForAssertStringContainsString()
    {
        $testString = "geekforgeek";
        $substring = "geeks"; 
        // assert function to test whether 'geeks' is a substring of testString
        $this->assertStringContainsString($substring, $testString, "testString doesn't contains 'geeks' as substring") ;
    }
}

?>

PHPUnit 8.2.5 by Sebastian Bergmann and contributors.

F                                                                   1 / 1 (100%)

Time: 65 ms, Memory: 10.00 MB

There was 1 failure:

1) GeeksPhpunitTestCase::testNegativeTestcaseForAssertStringContainsString
testString doesn't contains 'geeks' as substring
Failed asserting that 'geekforgeek' contains "geeks".

/home/shivam/Documents/geeks/phpunit/abc.php:11

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

<?php
use PHPUnit\Framework\TestCase;

class GeeksPhpunitTestCase extends TestCase
{
    public function testPositiveTestcaseForAssertStringContainsString()
    {
        $testString = "geekforgeek";
        $substring = "geek"; 
        // assert function to test whether 'geeks' is a substring of testString
        $this->assertStringContainsString($substring, $testString, "testString doesn't contains 'geeks' as substring") ;
    }
}

?>

PHPUnit 8.2.5 by Sebastian Bergmann and contributors.

.                                                                   1 / 1 (100%)

Time: 67 ms, Memory: 10.00 MB

OK (1 test, 1 assertion)