Adds isWaiting to mockClock to remove sleep in testsales

tests/codex/helpers/mockclock.nim

@@ -40,3 +40,6 @@ method waitUntil*(clock: MockClock, time: SecondsSince1970) {.async.} =
     let future = newFuture[void]()
     clock.waiting.add(Waiting(until: time, future: future))
     await future
+
+proc isWaiting*(clock: MockClock): bool =
+  clock.waiting.len > 0

tests/codex/sales/testsales.nim

@@ -190,7 +190,7 @@ asyncchecksuite "Sales":
 
   proc allowRequestToStart {.async.} =
     # wait until we're in initialproving state
-    await sleepAsync(10.millis)
+    check eventually clock.isWaiting
     # it won't start proving until the next period
     await clock.advanceToNextPeriod(market)