add promise context test

Author: shikokuchuo

tests/tests.R

@@ -241,6 +241,7 @@ nanotest(!until_(cv, 10))
 nanotestz(cv_reset(cv))
 nanotestz(cv_value(cv))
 nanotestaio(cs <- request_signal(req$context, "test", send_mode = "next", cv = cv, timeout = 500))
+nanotestaio(set_promise_context(cs, environment()))
 nanotest(typeof(ctxn <- .context(rep)) == "externalptr")
 nanotestaio(cr <- recv_aio_signal(ctxn, cv = cv, timeout = 500))
 nanotest(call_aio(cr)$data == "test")