Fix a test exception

src/Grant/AbstractGrant.php

@@ -158,7 +158,6 @@ protected function validateClient(ServerRequestInterface $request): ClientEntity
 
             throw OAuthServerException::invalidClient($request);
         }
-
         $client = $this->getClientEntityOrFail($clientId, $request);
 
         // If a redirect URI is provided ensure it matches what is pre-registered

tests/Grant/DeviceCodeGrantTest.php

@@ -458,6 +458,7 @@ public function testRespondToRequestMissingDeviceCode(): void
         $client->setIdentifier('foo');
         $clientRepositoryMock = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
         $clientRepositoryMock->method('getClientEntity')->willReturn($client);
+        $clientRepositoryMock->method('validateClient')->willReturn(true);
 
         $refreshTokenRepositoryMock = $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock();
         $refreshTokenRepositoryMock->method('persistNewRefreshToken')->willReturnSelf();
@@ -492,9 +493,8 @@ public function testRespondToRequestMissingDeviceCode(): void
 
         $responseType = new StubResponseType();
 
-        // TODO: We need to be more specific with this exception
-        // We should add an error that says the device code is missing perhaps?
         $this->expectException(OAuthServerException::class);
+        $this->expectExceptionCode(3);
 
         $grant->respondToAccessTokenRequest($serverRequest, $responseType, new DateInterval('PT5M'));
     }