No unit testing, no integration testing (as was admitted) and no production sanity test at all. I guess the accountant was asleep at the wheel as well.
You have bigger issues than strong types.
> But how strong and reliable are your test environments to ensure that this all works correctly? How much effort, time, and money does it take to maintain full testing solutions?
Seriously? The entire company revenue depends on counting ad views and you don't have resources to make sure you're counting right? Oh, c'mon!
Strong typing has its place, but this was a bad argument in favor of it...
The resolution of the post mortem was to both add 'an' (they were already set up for it) integration test, and strict typing.
The criticism of the test was that it would only cover that specific path, not others or potential future ones. Which is true.
It could have been one of the many components displaying ads. And this specific component might have accounted for a small percentage of those ads.
And presumably this wasn’t the only feature deployed so any noticeable change in revenues could have been attributed to many other things before a typo in the ID would have been discovered.
It's like the types are one giant unit test for them.
So both of these would have been good, none of them was clearly bad. Notice that you don't necessarily have to choose between these two.