Add ability to register commands

command/command.go

@@ -19,6 +19,10 @@ func DebugCommands() *Commands {
 	return &Commands{cmds}
 }
 
+func (c *Commands) Register(cmdstr string, cf cmdfunc) {
+	c.cmds[cmdstr] = cf
+}
+
 func (c *Commands) Find(cmdstr string) cmdfunc {
 	cmd, ok := c.cmds[cmdstr]
 	if !ok {

command/command_test.go

@@ -1,6 +1,9 @@
 package command
 
-import "testing"
+import (
+	"fmt"
+	"testing"
+)
 
 func TestCommandDefault(t *testing.T) {
 	var (
@@ -17,3 +20,20 @@ func TestCommandDefault(t *testing.T) {
 		t.Fatal("wrong command output")
 	}
 }
+
+func TestCommandRegister(t *testing.T) {
+	cmds := Commands{make(map[string]cmdfunc)}
+
+	cmds.Register("foo", func() error { return fmt.Errorf("registered command") })
+
+	cmd := cmds.Find("foo")
+
+	err := cmd()
+	if err == nil {
+		t.Fatal("cmd was not found")
+	}
+
+	if err.Error() != "registered command" {
+		t.Fatal("wrong command output")
+	}
+}