diff --git a/modules/openapi-generator/src/main/resources/php-flight/register_routes_test.mustache b/modules/openapi-generator/src/main/resources/php-flight/register_routes_test.mustache
index ad45d9fcca6..cdb3e8cc265 100644
--- a/modules/openapi-generator/src/main/resources/php-flight/register_routes_test.mustache
+++ b/modules/openapi-generator/src/main/resources/php-flight/register_routes_test.mustache
@@ -26,7 +26,7 @@ class RegisterRoutesTest extends \PHPUnit\Framework\TestCase {
         {{/operations}}
         };
         \{{invokerPackage}}\RegisterRoutes::registerRoutes($handler);
-        $this->assertTrue(true);
+        self::assertTrue(true);
     }
 {{/apis}}
 {{#models}}
@@ -41,7 +41,7 @@ class RegisterRoutesTest extends \PHPUnit\Framework\TestCase {
         {{/-first}}
         {{/enumVars}}
         {{/allowableValues}}
-        $this->assertEquals(
+        self::assertEquals(
             parseParam($value, '\\{{escapedModelPackage}}\\{{classname}}'),
             \{{modelPackage}}\{{classname}}::{{#allowableValues}}{{#enumVars}}{{#-first}}{{{name}}}{{/-first}}{{/enumVars}}{{/allowableValues}}
         );
diff --git a/samples/server/petstore/php-flight/Test/RegisterRoutesTest.php b/samples/server/petstore/php-flight/Test/RegisterRoutesTest.php
index 737debbe455..e95aed2e9f8 100644
--- a/samples/server/petstore/php-flight/Test/RegisterRoutesTest.php
+++ b/samples/server/petstore/php-flight/Test/RegisterRoutesTest.php
@@ -29,7 +29,7 @@ class RegisterRoutesTest extends \PHPUnit\Framework\TestCase {
             }
         };
         \OpenAPIServer\RegisterRoutes::registerRoutes($handler);
-        $this->assertTrue(true);
+        self::assertTrue(true);
     }
     public function testRegisterRoutesAbstractStoreApi(): void
     {
@@ -39,7 +39,7 @@ class RegisterRoutesTest extends \PHPUnit\Framework\TestCase {
             }
         };
         \OpenAPIServer\RegisterRoutes::registerRoutes($handler);
-        $this->assertTrue(true);
+        self::assertTrue(true);
     }
     public function testRegisterRoutesAbstractUserApi(): void
     {
@@ -49,12 +49,12 @@ class RegisterRoutesTest extends \PHPUnit\Framework\TestCase {
             }
         };
         \OpenAPIServer\RegisterRoutes::registerRoutes($handler);
-        $this->assertTrue(true);
+        self::assertTrue(true);
     }
     public function testParseParamsEnumFindPetsByStatusStatusParameterInner(): void
     {
         $value = 'available';
-        $this->assertEquals(
+        self::assertEquals(
             parseParam($value, '\\OpenAPIServer\\Model\\FindPetsByStatusStatusParameterInner'),
             \OpenAPIServer\Model\FindPetsByStatusStatusParameterInner::AVAILABLE
         );
@@ -62,7 +62,7 @@ class RegisterRoutesTest extends \PHPUnit\Framework\TestCase {
     public function testParseParamsEnumOrderStatus(): void
     {
         $value = 'placed';
-        $this->assertEquals(
+        self::assertEquals(
             parseParam($value, '\\OpenAPIServer\\Model\\OrderStatus'),
             \OpenAPIServer\Model\OrderStatus::PLACED
         );
@@ -70,7 +70,7 @@ class RegisterRoutesTest extends \PHPUnit\Framework\TestCase {
     public function testParseParamsEnumPetStatus(): void
     {
         $value = 'available';
-        $this->assertEquals(
+        self::assertEquals(
             parseParam($value, '\\OpenAPIServer\\Model\\PetStatus'),
             \OpenAPIServer\Model\PetStatus::AVAILABLE
         );