What is src/hash/test_gen.awk in Go's source code for?

[Arkadiusz Drabczyk]

There is src/hash/test_gen.awk in Go's source code repo. It was added
back in 2008. It's not called anywhere, at least directly, go binary
can be built successfully after removing it and 'git log --all -S
test_gen' finds only the commit that added it. Also, I'm not sure what
'cmd = "echo -n `9 sha1sum`' is supposed to do. Can you explain?

--
Arkadiusz Drabczyk

[Sean Liao]

The comment in the file explains that it' was used to generate test cases, used:

https://go.googlesource.com/go/+/e3b793004fe9fb169099026e8c8d732913ec2ffa/src/lib/hash/sha1_test.go#20

A variant of the test still exists,

https://go.googlesource.com/go/+/refs/heads/master/src/crypto/sha1/sha1_test.go#25

It appears to just be leftover / didn't get cleaned up or moved with sha1.

9 <command> is

https://9fans.github.io/plan9port/man/man1/9.html