message: addCommand implementation
diff: @@ -26,6 +26,14 @@ export default class TestCase {
  }
  }
  + @action.bound addCommand(command) {
  + if (!command || command.constructor.name !== "Command") {
  + throw new Error(`Expected to receive Command instead received ${command ? command.constructor.name : command}`);
  + } else {
  + this.commands.push(command);
  + }
  + }
  +
  @action.bound insertCommandAt(command, index) {
  if (!command || command.constructor.name !== "Command") {
  throw new Error(`Expected to receive Command instead received ${command ? command.constructor.name : command}`);
  