Clean up

tests/PersistenceWriterTests.cpp

@@ -54,7 +54,7 @@ void TestDebouncedRequestsCoalesceToNewestSnapshot()
 	Expect(metrics.enqueuedCount == 1, "first debounced snapshot counts as enqueue");
 	Expect(metrics.coalescedCount == 1, "second debounced snapshot counts as coalesced");
 
-	writer.StopAndFlush();
+	Expect(writer.StopAndFlush(std::chrono::seconds(1), error), "flush drains debounced snapshots");
 
 	{
 		std::lock_guard<std::mutex> lock(mutex);
@@ -87,7 +87,7 @@ void TestImmediateRequestsAreNotCoalesced()
 	std::string error;
 	Expect(writer.EnqueueSnapshot(first, error), "first immediate snapshot enqueues");
 	Expect(writer.EnqueueSnapshot(second, error), "second immediate snapshot enqueues");
-	writer.StopAndFlush();
+	Expect(writer.StopAndFlush(std::chrono::seconds(1), error), "flush drains immediate snapshots");
 
 	{
 		std::lock_guard<std::mutex> lock(mutex);
@@ -116,7 +116,7 @@ void TestWriteFailureReportsStructuredResult()
 
 	std::string error;
 	Expect(writer.EnqueueSnapshot(snapshot, error), "failing snapshot still enqueues");
-	writer.StopAndFlush();
+	Expect(writer.StopAndFlush(std::chrono::seconds(1), error), "flush reports failing snapshot result");
 
 	Expect(results.size() == 1, "writer reports one failure result");
 	Expect(!results.empty() && !results[0].succeeded, "writer result records failure");