Fixing tests

Most were a case of adding void return statement to setUp and tearDown,
also needed to add 6th `null` param to indieauth method. Its for
code_verifier, issue created to work out what I should actually be doing
with that.

app/Http/Controllers/TokenEndpointController.php

@@ -48,7 +48,8 @@ class TokenEndpointController extends Controller
                 request()->input('code'),
                 request()->input('me'),
                 request()->input('redirect_uri'),
-                request()->input('client_id')
+                request()->input('client_id'),
+                null // code_verifier
             );
             if (array_key_exists('me', $auth)) {
                 $scope = $auth['scope'] ?? '';