Merge pull request #5354 from carusogabriel/refactoring-tests

Refactoring tests

Conflicts resolved:
	tests/codeigniter/core/Utf8_test.php
	tests/codeigniter/database/query_builder/group_test.php
	tests/codeigniter/libraries/Form_validation_test.php
diff --git a/tests/codeigniter/libraries/Form_validation_test.php b/tests/codeigniter/libraries/Form_validation_test.php
index fa9e86c..3280f5b 100644
--- a/tests/codeigniter/libraries/Form_validation_test.php
+++ b/tests/codeigniter/libraries/Form_validation_test.php
@@ -358,7 +358,7 @@
 		$this->form_validation->run();
 		$error_msg = $this->form_validation->error('foo');
 
-		$this->assertTrue(strrpos($error_msg, $prefix) === 0);
+		$this->assertStringStartsWith($prefix, $error_msg);
 		$this->assertTrue(strrpos($error_msg, $suffix, -strlen($suffix)) === (strlen($error_msg) - strlen($suffix)));
 
 		$_POST = array();