Added checks to make sure the specified track exists

Added precondition checks to validate input files and paths to return more informative error messages as per #2

node_modules/jest-util/build/ErrorWithStack.js

@@ -0,0 +1,24 @@
+'use strict';
+
+Object.defineProperty(exports, '__esModule', {
+  value: true
+});
+exports.default = void 0;
+
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+class ErrorWithStack extends Error {
+  constructor(message, callsite) {
+    super(message);
+
+    if (Error.captureStackTrace) {
+      Error.captureStackTrace(this, callsite);
+    }
+  }
+}
+
+exports.default = ErrorWithStack;