An important part of the process process of learning a new language is to learn the ecosystem that helps you to write better code. In a previous article I covered gdb integration with Go.
Next on my list is to find an equivalent of the fantastic Python coverage tool coverage.py. The Go equivalent is called gocov.
Let’s go ahead and install it now:
$ go get github.com/axw/gocov/gocov
$ go install github.com/axw/gocov/gocov
gocov progam in your $GOPATH/bin. I would recommend adding this to your $PATH:
export PATH=$PATH:$GOPATH/bin
gocov in conjunction with our test suite. Here’s an example of running the test suite via gocov, generating a coverage report, and then immediately viewing that report via the less command.
$ gocov test <myprogram> | gocov report | less
[...]
dispatch/dispatch.go Dispatcher.String 100.00% (8/8)
dispatch/dispatch.go NewDispatcher 100.00% (2/2)
dispatch/dispatch.go Dispatcher.RefreshPlugins 100.00% (2/2)
dispatch/dispatch.go Dispatcher.Dispatch 83.33% (5/6)
[...]$ gocov test <myprogram> > coverage.json
$ gocov annotate coverage.json dispatch.Dispatcher.Dispatch
33 func (self *Dispatcher) Dispatch(l *line.Line) {
34
35 activePlugins := self.plugins[l.ChatBotId]
36
37 var err error
38 for _, plugin := range activePlugins {
39 err = self.queue.Publish(PUBSUB_PREFIX+plugin.Name, l.AsJson())
40 if err != nil {
41 MISS log.Fatal("Error writing (PUBLISH) to queue. ", err)
42 }
43 }
44 }
gocov is a convenient tool that helps to guide you in writing tests for your program. Since it outputs to stdout you can use it in conjunction with grep, sort, less, etc.
[Edited – 2013-01-09]: Amended the article to reflect the feedback I got on reddit.com/r/golang