Completed duplicate database in multiple sessions.

src/morethantext/mod.rs

@@ -162,7 +162,10 @@ mod mtt {
         let output = mtt2.commit(store2).await;
         match output {
             Ok(_) => assert!(false, "Should have returned an error"),
-            Err(_) => (),
+            Err(err) => match err.code {
+                ErrorCode::DuplicateDatabase(_) => (),
+                _ => assert!(false, "{:?} is not ErrorCode::DuplicateDatabase", err.code),
+            },
         }
     }
 }