go - how to compare funcs in golang -

i'm attempting write test package , failing @ comparing funcs. here's i'm doing.

package main  import (     "fmt"     "reflect" )  type handlerfunc func(cmd interface{})  type bus struct {     handlers map[reflect.type]handlerfunc }  func (bus *bus) registerhandler(cmd interface{}, handler handlerfunc) {     bus.handlers[reflect.typeof(cmd)] = handler }  func (bus *bus) gethandler(cmd interface{}) handlerfunc {     t := reflect.typeof(cmd)      kind, handler := range bus.handlers {         if t == kind {             return handler         }     }      return nil }  func new() *bus {     return &bus{         handlers:    make(map[reflect.type]handlerfunc),     } }  type registerusercommand struct {}  func main() {     bus := new()     handler := func (cmd interface{}) {}      bus.registerhandler(&registerusercommand{}, handler)      retrieved := bus.gethandler(&registerusercommand{})      if retrieved != handler {         fmt.println("not same!")         return     }      fmt.println("same!") } 

comparing retrieved handler causes following error

invalid operation: (func(interface {}))(retrieved) != handler (func can compared nil) 

how can test function i'm retrieving same 1 added previously?

given can't compare functions, can write test in different way. can make handler set boolean value in test , check you've got right function calling , seeing if boolean changes.

here's example:

func main() {     bus := new()     called := false     handler := func (cmd interface{}) { called = true }      bus.registerhandler(&registerusercommand{}, handler)     bus.gethandler(&registerusercommand{})(nil)      if called {         fmt.println("we got right handler!")         return     }      fmt.println("we didn't right handler") }