@Override
  public Store getStore(PartitionId id, boolean skipStateCheck) {
    if (!firstCall) {
      try {
        waitOperationCountdown.await();
      } catch (InterruptedException e) {
        throw new IllegalStateException("CountDown await was interrupted", e);
      }
    }
    firstCall = false;
    Store storeToReturn;
    if (overrideStoreToReturn != null) {
      storeToReturn = overrideStoreToReturn;
    } else if (returnNullStore) {
      storeToReturn = null;
    } else if (!storeMap.isEmpty()) {
      storeToReturn = storeMap.get(id);
      if (storeToReturn == null) {
        unreachablePartitions.add(id);
      }
    } else {
      storeToReturn = store;
    }
    return storeToReturn;
  }
The {@link PartitionId} that was provided in the call to {@link #startBlobStore(PartitionId)}
ambry-server/src/test/java/com/github/ambry/server/MockStorageManager.java