message: unused imports.
diff: import { assert } from "chai";
  import * as path from "path";
  import * as sinon from "sinon";
  -import { Guid, IModelStatus } from "@itwin/core-bentley";
  -import { IModelError } from "@itwin/core-common";
  +import { Guid } from "@itwin/core-bentley";
  import { CheckpointManager, V1CheckpointManager, V2CheckpointManager } from "../../CheckpointManager";
  import { IModelHost } from "../../core-backend";
  import { SnapshotDb } from "../../IModelDb";
  