updated deleteOperation in OperationServiceImpl

opp/core/src/main/java/OperationServiceImpl.java

@@ -75,6 +75,10 @@ public class OperationServiceImpl implements OperationService {
 
     public Operation delete(Operation.Delete del) throws Exception {
 
-        return repo.deleteOperation(del.id());
+        Optional<Operation> foundOperation =  repo.findOperation(del.id());
+        if (foundOperation.isPresent()) {
+            return repo.deleteOperation(del.id());
+        }
+        return null;
     }
 }

opp/jdbc-repo-impl/src/test/java/Tests.java

@@ -342,6 +342,7 @@ public final class Tests
       throw new Exception();
     }
   }
+
 @Ignore
   @Test
   public void testDeleteOperation() throws Exception {
@@ -355,7 +356,7 @@ public final class Tests
 
     Operation deleteOperation = operationService.process(deleteCommand);
 
-    assertFalse(repo.findOperation(deleteOperation.id()).isPresent());
+   assertFalse(repo.findOperation(deleteOperation.id()).isPresent());
   }
 
   @Ignore