# assertStringStartsWith() >[info] ## assertStringStartsWith(string $prefix, string $string[, string $message = '']) 当 `$string` 不以 `$prefix` 开头时报告错误，错误讯息由 `$message` 指定。 `assertStringStartsNotWith()` 是与之相反的断言，并接受相同的参数。 **Example A.41. assertStringStartsWith() 的用法** ~~~ <?php class StringStartsWithTest extends PHPUnit_Framework_TestCase { public function testFailure() { $this->assertStringStartsWith('prefix', 'foo'); } } ?> ~~~ ~~~ phpunit StringStartsWithTest PHPUnit 5.0.0 by Sebastian Bergmann and contributors. F Time: 0 seconds, Memory: 5.00Mb There was 1 failure: 1) StringStartsWithTest::testFailure Failed asserting that 'foo' starts with "prefix". /home/sb/StringStartsWithTest.php:6 FAILURES! Tests: 1, Assertions: 1, Failures: 1. ~~~