Test cases can be as long as short as they need to be. They can cover a lot of requirements in one go, or maybe just even one.
And yet many metrics for covering test progress seem to fall back on "what percentage of test cases are complete".
Think for a while about this fruit bowl ...
If I told you that today my team had finished off 5 pieces of fruit, how much would be left for the next few days? I bet you'd hope (if you're the business owner) that one of those pieces of fruit was the watermelon. But what if it was just 5 grapes?
That's what happens when you count test cases, you're saying a grape is the same amount of fruit as an apple ... or a watermelon.
If you can find a better way to track when we're out of fruit, please comment below ...