Cobra + Viper Golang How to test subcommands? - go

Question

I am developing an web app with Go. So far so good, but now I am integrating Wercker as a CI tool and started caring about testing. But my app relies heavily on Cobra/Viper configuration/flags/environment_variables scheme, and I do not know how to properly init Viper values before running my test suite. Any help would be much appreciated.

Answer 1

When I use Cobra/Viper or any other combination of CLI helpers, my way of doing this is to have the CLI tool run a function whose sole purpose will be to get arguments and pass them to another method who will do the actual work.
Here is a short (and dumb) example using Cobra :
package main
import (
"fmt"
"os"
"github.com/spf13/cobra"
)
func main() {
var Cmd = &cobra.Command{
Use: "boom",
Short: "Explode all the things!",
Run: Boom,
}
if err := Cmd.Execute(); err != nil {
fmt.Println(err)
os.Exit(-1)
}
}
func Boom(cmd *cobra.Command, args []string) {
boom(args...)
}
func boom(args ...string) {
for _, arg := range args {
println("boom " + arg)
}
}
Here, the Boom function is hard to test, but the boom one is easy.
You can see another (non-dumb) example of this here (and the correspond test here).

Answer 2

i have found an easy way to test commands with multiple level sub commands, it is not professional but it worked well.
assume we have a command like this
RootCmd = &cobra.Command{
Use: "cliName",
Short: "Desc",
}
SubCmd = &cobra.Command{
Use: "subName",
Short: "Desc",
}
subOfSubCmd = &cobra.Command{
Use: "subOfSub",
Short: "Desc",
Run: Exec
}
//commands relationship
RootCmd.AddCommand(SubCmd)
SubCmd.AddCommand(subOfSubCmd)
When testing the subOfSubCmd we can do this way:
func TestCmd(t *testing.T) {
convey.Convey("test cmd", t, func() {
args := []string{"subName", "subOfSub"}
RootCmd.SetArgs(args)
RootCmd.Execute()
})
}