Smoke alarms testing

When it comes to actually testing the smoke alarms, I have read that it is not enough to just push the button to check if the smoke alarm is working, this actually only tells you that the sound is working on the alarm, I have seen detectasmoke canisters online that simulate a fire, this will actually test your smoke alarms, you can get detectagas canisters for co2 monitors, my worry is this, if a fire broke out and they check my check book, and it just says that I pushed the button, is that enough to cover me, when there is actually more I could have done, or am I being to paranoid in buying these things? also they are not that cheap.