test: de-flake jobProgressPublisherEmitsExecutingEvents

The progress publisher is a hot SubmissionPublisher with no replay, and
the subscriber can only attach after backtest() returns the handle. With
the sub-millisecond test poll interval, the STARTED to COMPLETED loop
could emit both EXECUTING events and close the publisher before the
subscriber attached, so the assertion occasionally saw no EXECUTING event.

Hold the first execution poll until the subscriber is attached via a
latch counted down in onSubscribe, making the observation deterministic.
Test-only change; no production behavior is affected.

Author: mrmx

src/test/java/com/qtsurfer/api/sdk/workflows/DomainObjectsTest.java

@@ -117,10 +117,19 @@ void jobProgressPublisherEmitsExecutingEvents() throws Exception {
                 .thenReturn(new JobState().status(JobState.StatusEnum.COMPLETED).size(1).completed(1));
         when(backtestingApi.executeBacktesting(anyString(), eq(DataSourceType.TICKER), any(ExecuteBacktestingRequest.class)))
                 .thenReturn(new AcceptedJob().jobId("exec-2"));
+        // The progress publisher is hot (SubmissionPublisher, no replay) and the
+        // subscriber can only attach after backtest() returns the handle, by which
+        // point the sub-millisecond poll loop may already have emitted the EXECUTING
+        // events and closed. Hold the first EXECUTING poll until the subscriber is
+        // attached so the event is observed deterministically.
+        CountDownLatch subscribed = new CountDownLatch(1);
         when(backtestingApi.getExecutionResult(anyString(), eq(DataSourceType.TICKER), eq("exec-2")))
-                .thenReturn(new BacktestJobResult()
-                        .state(new JobState().status(JobState.StatusEnum.STARTED).size(100).completed(25))
-                        .results(new ResultMap()))
+                .thenAnswer(inv -> {
+                    assertTrue(subscribed.await(5, TimeUnit.SECONDS), "subscriber attached before first EXECUTING poll");
+                    return new BacktestJobResult()
+                            .state(new JobState().status(JobState.StatusEnum.STARTED).size(100).completed(25))
+                            .results(new ResultMap());
+                })
                 .thenReturn(new BacktestJobResult()
                         .state(new JobState().status(JobState.StatusEnum.COMPLETED).size(100).completed(100))
                         .results(new ResultMap().strategyId("strategy-abc")));
@@ -132,7 +141,7 @@ void jobProgressPublisherEmitsExecutingEvents() throws Exception {
         CountDownLatch complete = new CountDownLatch(1);
         job.progress().subscribe(new Flow.Subscriber<>() {
             Flow.Subscription sub;
-            @Override public void onSubscribe(Flow.Subscription s) { sub = s; s.request(Long.MAX_VALUE); }
+            @Override public void onSubscribe(Flow.Subscription s) { sub = s; s.request(Long.MAX_VALUE); subscribed.countDown(); }
             @Override public void onNext(BacktestProgress p) { seen.add(p); }
             @Override public void onError(Throwable t) { complete.countDown(); }
             @Override public void onComplete() { complete.countDown(); }