def METHOD_NAME(oauth2_settings, issuer_setting, request_type, rf):
    oauth2_settings.OIDC_ISS_ENDPOINT = issuer_setting
    if request_type == "django":
        request = rf.get("/")
    elif request_type == "oauthlib":
        request = Request("/", headers=rf.get("/").META)
    expected = issuer_setting or "http://testserver/o"
    assert oauth2_settings.oidc_issuer(request) == expected