Friday, January 23, 2026
HomeLanguagesPHPUnit assertStringStartsWith() Function

PHPUnit assertStringStartsWith() Function

The assertStringStartsWith() function is a builtin function in PHPUnit and is used to assert whether the actual string starts with expected prefix string or not. This assertion will return true in the case if the actual string starts with expected prefix string else returns false. In case of true the asserted test case got passed else test case got failed.

Syntax:

assertStringStartsWith(string $prefix, string $string
[, string $message = ''])

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

  • $expectedprefix: This parameter is of any type which represents the expected prefix string.
  • $actualstring: This parameter is of any type which represents the actual 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 assertStringStartsWith() function in PHPUnit:

Example 1:

PHP




<?php 
use PHPUnit\Framework\TestCase; 
    
class GeeksPhpunitTestCase extends TestCase 
{ 
    public function testNegativeTestcaseForassertStringStartsWith()
    { 
        $expectedprefix = ('dis');
        $actualstring = ('agreedis');
    
        // Assert function to test whether 
        // actual string content starts with 
        // expected prefix string content or not
        $this->assertStringStartsWith(
            $expectedprefix,
            $actualstring, 
            "actual string content start with expected 
             prefix content or not"
        ); 
    } 
} 
    
?>


Output:

PHPUnit 8.5.8 by Sebastian Bergmann and contributors.

F                                                         1 / 1 (100%)

Time: 89 ms, Memory: 10.00 MB

There was 1 failure:

1) GeeksPhpunitTestCase::testNegativeTestcaseForassertStringStartsWith
actual string content start with expected prefix content or not
Failed asserting that 'agreedis' starts with "dis".

/home/lovely/Documents/php/test.php:17

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

Example 2:

PHP




<?php 
use PHPUnit\Framework\TestCase; 
    
class GeeksPhpunitTestCase extends TestCase 
{ 
    public function testPositiveTestcaseForassertStringStartsWith()
    { 
        $expectedprefix = ('dis');
        $actualstring = ('disagree');
    
        // Assert function to test whether 
        // actual string content starts with 
        // expected prefix string content or not
        $this->assertStringStartsWith(
            $expectedprefix,
            $actualstring, 
            "actual string content start with expected 
             prefix content or not"
        ); 
    } 
} 
    
?>


Output:

PHPUnit 8.5.8 by Sebastian Bergmann and contributors.

.                                                 1 / 1 (100%)

Time: 88 ms, Memory: 10.00 MB

OK (1 test, 1 assertion)

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

RELATED ARTICLES

Most Popular

Dominic
32475 POSTS0 COMMENTS
Milvus
119 POSTS0 COMMENTS
Nango Kala
6847 POSTS0 COMMENTS
Nicole Veronica
11977 POSTS0 COMMENTS
Nokonwaba Nkukhwana
12065 POSTS0 COMMENTS
Shaida Kate Naidoo
6986 POSTS0 COMMENTS
Ted Musemwa
7221 POSTS0 COMMENTS
Thapelo Manthata
6934 POSTS0 COMMENTS
Umr Jansen
6912 POSTS0 COMMENTS