This is great. I hope it lands in the next version.

CL https://golang.org/cl/9635 mentions this issue.

We'd also want to make any failures be reproducible later. That implies a PRNG, and printing the seed in test failures. So maybe -testing.shuffle should not be a custom flag type (boolean or seed value), or there should be a second flag to set the seed.

I'd suggest two flags, a boolean to shuffle with a default seed(time), and a flag which takes a seed as a parameter. When a test fails print out the seed used. I think this would work, because as a user I would only care about the seed if I needed to reproduce a failure case.

I like what @jasdel say.

• shuffle (boolean)
• seed (integer)

I'm not sure that we should shuffle benchmarks. Re-arranging benchmarks, particularly microbenchmarks, can result in apparent performance changes: #7920. Also, benchcmp assumes that benchmarks have a stable order. This helps get good results when benchmarks in different packages have the same name. It is also what makes the -best flag possible.

Marking Go1.6Early. I think there's a lot of design left here.

The design did not happen, so not for Go 1.6. If someone is interested, please file a new proposal issue (golang.org/s/proposal). We'll probably need a design doc.