colog is a concurrent log. In the JS version of Orbit it is currently called log, but in many contexts a log is a linear sequence of events. To avoid confusion, the Go version was named colog.
go get the package, including the deps for tests (-t):
go get -t github.com/keks/go-ipfs-colog
Once successfully installed
go test github.com/keks/go-ipfs-colog
does the trick.
You can find the API reference on godoc.