I'd be totally unsurprised if the "emergency call" functionality, despite its life-saving importance and thus the necessity of testing it does not actually have any formal test systems in most or perhaps all countries. That is, you can "just" take a phone you're testing out to the real world, dial 112 and then apologise when you get through, but there's no way to test without wasting critical resources in this way.
This was certainly true for COSPAS/SARSAT's distress beacons until relatively late in their history. The best you could do was inform the SAR resources in your country of your intention to test, tell them you don't need rescuing, then activate the beacon. Most likely they would ask you not to, and often it was technically illegal, regardless of the necessity of running such tests during development and benchmarking.