[tehlike]

It should be taken as a given that testing is necessary but not sufficient to prevent production outages, or limit their impact.

Monitoring, canaries, experimantations do need to be adopted at pretty much everywhere possible.

[runeks]

> It should be taken as a given that testing is necessary but not sufficient to prevent production outages […]

That depends on how good your tests are.

[tehlike]

And how good your employees are... How good your review process is... How good xyz is...

If your engineers are so solid, and them making a mistake on a given release is individually 0.5%, and you have 50 engineers, you will see the probability of nothing going wrong is about 77%(0.995^50), and something going wrong is 1-0.995^50. Pretty low, i might say.

Dont do this to your engineers. 80% test coverage is a sweet spot, the rest is caught better with other approaches. No reason to kill engineers productivity everytime something fails on production by blaming their tests arent good.

[hamandcheese]

The probability of something going wrong should be 1-(P(something_nothing_wrong))

In this example, that’s 23%.