`this._iccCard` should not be null at this point, that's weird. Is there any special circumstance under you are performing the test? I would prefer to test if the following change solves the issue as well.

Just add this line please.

```
    if (this._addedListener) {
      // Otherwise, unregister.
      this._iccCard = iccManager.getIccById(this._iccId);
      /* ... */
    }
```