- $req->assertElementExists('form[action$="/saml2/login"][method=POST][id="login-form"] button');
- $req->assertElementExists('button[form="login-form"]');
+ $this->withHtml($req)->assertElementExists('form[action$="/saml2/login"][method=POST][id="login-form"] button');
+ $this->withHtml($req)->assertElementExists('button[form="login-form"]');