Feature request: Only run assertions (--skip-command?)

[stianlagstad]

Thank you again for this valuable tool.

Sometimes I have an expensive command which takes a long time, and in those cases I would like the ability to only run that command once and then iterate on my assertions without having to re-run the command. Could that be made possible with something like a flag --skip-command, or with something like --only-run-assertions?

[rhpvorderman]

This is similar to #174 if I am not mistaken. Yes, this would be very useful to have!

[stianlagstad]

Thank you. Closing in favor of #176.