Like many others, this was the wakeup call I needed to download go1.18beta1 and start writing some fuzz tests. I unleashed it upon my JSON log viewer, which ha

Like many others, this was the wakeup call I needed to download go1.18beta1 and start writing some fuzz tests. I unleashed it upon my JSON log viewer, which has the goal of never suppressing a line even in the face of egregious parse errors. (The last thing you need when software goes wrong is your UI hiding stuff from you, after all.) As expected, within seconds it found that the input `{"": 0}` causes a panic. (This is a weird special case that I handled for other classes of this problem, but not this exact case!) I also got to see what happens when you have more bytes on a line than bufio.MaxScanTokenSize and realized that that is pretty low for an interactive program, especially when all you can do is exit. The ergonomics are excellent. When the fuzzer finds a failing input, it creates a file that contains the test case. You check this in and future invocations of plain "go test ./..." will use this input. "go test -fuzz=FuzzWhatever what/ever" will cause it to search for more failing inputs. Really well-designed.