Can't get flow type coverage for a function

I have the following function:

type KeyboardInfo = {
  key?: string,
  code?: string,
  meta?: boolean,
  alt?: boolean,
  ctrl?: boolean,
  shift?: boolean,
  prevent?: boolean,
  log?: boolean
}

function on(event: KeyboardEventTypes, {key, meta, alt, code, shift, ctrl, prevent = true, log = false}: KeyboardInfo, callback: (e: KeyboardEvent) => void) {
  window.addEventListener(event, (e: KeyboardEvent) => {
    if (log) {
      console.log(e);
    }

    if (key && e.key !== key) {
      return;
    }
    if (meta && e.metaKey !== meta) {
      return;
    }
    if (code && e.code !== code) {
      return;
    }
    if (ctrl && e.ctrlKey !== ctrl) {
      return;
    }
    if (alt && e.altKey !== alt) {
      return;
    }
    if (shift && e.shiftKey !== shift) {
      return;
    }
    if (prevent) {
      e.preventDefault();
    }
    callback(e);
  });
}

I try to get this covered by flow, but I'm not sure how. Atom says it is not covered:

Is this because I call window? Not sure what is going on here.