> Sorry to say but that too is your fault. First thing you're supposed to do with tests is make them fail, then make them pass

They did not say they didn't do that, you're assuming.

If I were the person here, I might write a simple test with 'val1="foo"; val2="bar";' to make it fail. That would make it fail because the first byte is different, while I would think it failed because the entire value is different.

You might say that I should have also tried "bar" and "baz" (which would reveal the issue), but it's infeasible to try all possible inputs.

Most code is not written with exactly an excess of time to follow perfect practices every time, and so we must make tradeoffs.