private List<RouterStore.BlobIDAndVersion> getBlobIDAndVersionInHelix(int count) {
    // Verify that ZNRecord contains the right data.
    ZNRecord record = helixStore.get(RouterStore.ACCOUNT_METADATA_BLOB_IDS_PATH, null, AccessOption.PERSISTENT);
    assertNotNull("ZNRecord missing after update", record);
    List<String> accountBlobs = record.getListField(RouterStore.ACCOUNT_METADATA_BLOB_IDS_LIST_KEY);
    assertNotNull("Blob ids are missing from ZNRecord", accountBlobs);
    // version also equals to the number of blobs
    assertEquals("Number of blobs mismatch", count, accountBlobs.size());

    List<RouterStore.BlobIDAndVersion> blobIDAndVersions = new ArrayList<>(count);
    for (String json : accountBlobs) {
      blobIDAndVersions.add(RouterStore.BlobIDAndVersion.fromJson(json));
    }
    return blobIDAndVersions;
  }
Fetch the list of {@link RouterStore.BlobIDAndVersion} from the helixStore.
@param count The expected number of elements in the list.
@return The list of {@link RouterStore.BlobIDAndVersion}.
ambry-account/src/test/java/com/github/ambry/account/RouterStoreTest.java