I might come across as someone who hates testing, if the past two months have been anything to go by, but I've really been complaining about automating the tests, including some rather difficult ones to automate. But honesty compels me state this: the new regression test has found another potential bug.
Because I added code to delay (or entirely block) responses from the various database sources, a few test cases were added to a problematic feature to ensure it's been fixed. The Happy Path™ has been fixed, but there is a Sad Path™ that's been missed. We query two sources, A and B. In the scenario we are testing, the data we want is from B—any data from A is ignored (but we have to query anyway due to “reasons”). So the case of A has no data, B has data is fine. But it's when A doesn't return (or times out), the reponse from B is ignored when it probably shouldn't be (since that data does get back to us). And it would not surprise me if there aren't more cases like this.
Normally, I wouldn't expect this to happen all that much [It doesn't. We have a KPI for that, and I don't think it's worth worring about–the largest spike I've seen over the past month is easly three orders of magnitude lower than our volume; the rest barely show up on the graph. —Sean], and the re-engineering required to handle these casees might be significant since it would require adding more states to the processing state machine. But that's not my call to make.