SpringBoot: test GP can not be rejected twice

backend/src/main/java/djmil/cordacheckers/cordaclient/CordaClient.java

@@ -202,7 +202,7 @@ public class CordaClient {
 
         for (int retry = 0; retry < 6; retry++) {
             // Give Corda cluster some time to process our request
-            TimeUnit.SECONDS.sleep(retry*retry +1); // 1 2 5 8 17 33 sec
+            TimeUnit.SECONDS.sleep(retry*retry +2); // 2 3 6 10 18 27 sec
 
             final ResponseEntity<ResponseBody> responce = this.restTemplate.exchange(
                 "/flow/" 

backend/src/test/java/djmil/cordacheckers/cordaclient/CordaClientTest.java

@@ -110,6 +110,14 @@ public class CordaClientTest {
             holdingIdentityResolver.getByUsername(gpReceiver));
 
         assertThat(findByUuid(gpListReceiver, gpUuid)).isNull();
+
+        // GameProposal can not be rejected twice 
+        assertThatThrownBy(() -> {
+            cordaClient.gameProposalAction(
+                holdingIdentityResolver.getByUsername(gpSender),
+                gpUuid,
+                Action.REJECT);
+        });
     }
 
     private GameProposal findByUuid(List<GameProposal> gpList, UUID uuid) {