message: Provide default position
diff: @@ -18,7 +18,7 @@ const CURSOR = "[cursor]";
  class InMemoryEditor implements Editor {
  private codeMatrix: CodeMatrix = [];
  - private _position: Position;
  + private _position: Position = new Position(0, 0);
  constructor(code: Code, position: Position = new Position(0, 0)) {
  this.setCodeMatrix(code);
  