Wait for outstanding requests to be resolved before shutting down the directory queue.

service/src/test/java/org/whispersystems/textsecuregcm/sqs/DirectoryQueueTest.java

@@ -6,6 +6,8 @@
 package org.whispersystems.textsecuregcm.sqs;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.times;
@@ -15,6 +17,8 @@ import static org.mockito.Mockito.when;
 import java.util.List;
 import java.util.UUID;
 import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
 import java.util.stream.Stream;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -89,4 +93,35 @@ public class DirectoryQueueTest {
           sendMessageRequest.messageAttributes().get("action"));
     }
   }
+
+  @Test
+  void testStop() {
+    final CompletableFuture<SendMessageResponse> sendMessageFuture = new CompletableFuture<>();
+    when(sqsAsyncClient.sendMessage(any(SendMessageRequest.class))).thenReturn(sendMessageFuture);
+
+    final DirectoryQueue directoryQueue = new DirectoryQueue(List.of("sqs://test"), sqsAsyncClient);
+
+    final Account account = mock(Account.class);
+    when(account.getNumber()).thenReturn("+18005556543");
+    when(account.getUuid()).thenReturn(UUID.randomUUID());
+    when(account.isEnabled()).thenReturn(true);
+    when(account.isDiscoverableByPhoneNumber()).thenReturn(true);
+
+    directoryQueue.refreshAccount(account);
+
+    final CompletableFuture<Boolean> stopFuture = CompletableFuture.supplyAsync(() -> {
+      try {
+        directoryQueue.stop();
+        return true;
+      } catch (final Exception e) {
+        return false;
+      }
+    });
+
+    assertThrows(TimeoutException.class, () -> stopFuture.get(1, TimeUnit.SECONDS),
+        "Directory queue should not finish shutting down until all outstanding requests are resolved");
+
+    sendMessageFuture.complete(SendMessageResponse.builder().build());
+    assertTrue(stopFuture.join());
+  }
 }