commander

type Mock struct {
	Commands      map[string]bool   // which commands exist
	Responses     map[string]string // command pattern -> output
	Errors        map[string]error  // command pattern -> error
	RecordedCalls []RecordedCall    // all calls made
}

type Real struct{}

type RecordedCall struct {
	Name string
	Args []string
	Dir  string
}