In my current team of 3 dedicated testers and 3 dedicated developers we often find ourselves in a scenario towards the end of our sprint (usually the last 2-4 days of our 2 week sprint) where the developers have nothing to do yet cannot commit to any stretch goals because the testers are at full capacity testing the code written in the first half of the Sprint.
We have on occasion been asked to just commit to development work on a particular story but this feels wrong as it isn't potentially shippable at the end of the Sprint and we end up having a test only task for this story in the subsequent sprint. We have also tried asking the developers to test (this hasn't gone down well), but in any case the stretch task (based on the estimates) still won't fit into the Sprint.
I have a feeling that this is a common problem in SCRUM but I can't any solutions to this. I would appreciate if anybody has any experience in dealing with this situation.