/back, /away: Change no-op to return err

Fixes #402

When the user is not set as away, using the
`/back` or `/away` command should return error.
The previous behaviour was inconsistent,
`/away` sent a message and `/back` ignored it.
New behaviour is error for both cases.

Co-authored-by: Akshay <akshay.shekher@gmail.com>

chat/command.go

@@ -469,12 +469,13 @@ func InitCommands(c *Commands) {
 			msg.From().SetAway(awayMsg)
 			if awayMsg != "" {
 				room.Send(message.NewEmoteMsg("has gone away: "+awayMsg, msg.From()))
-			} else if !isAway {
-				room.Send(message.NewSystemMsg("Not away. Append a reason message to set away.", msg.From()))
-			} else {
+				return nil
+			}
+			if isAway {
 				room.Send(message.NewEmoteMsg("is back.", msg.From()))
+				return nil
 			}
-			return nil
+			return errors.New("not away. Append a reason message to set away")
 		},
 	})
 
@@ -486,8 +487,9 @@ func InitCommands(c *Commands) {
 			if isAway {
 				msg.From().SetAway("")
 				room.Send(message.NewEmoteMsg("is back.", msg.From()))
+				return nil
 			}
-			return nil
+			return errors.New("must be away to be back")
 		},
 	})
 

chat/command_test.go

@@ -25,10 +25,17 @@ func TestAwayCommands(t *testing.T) {
 		// expected output
 		IsUserAway  bool
 		AwayMessage string
+
+		// expected state change
+		ExpectsError func(awayBefore bool) bool
 	}
-	awayStep := step{"/away snorkling", true, "snorkling"}
-	notAwayStep := step{"/away", false, ""}
-	backStep := step{"/back", false, ""}
+	neverError := func(_ bool) bool { return false }
+	// if the user was away before, then the error is expected
+	errorIfAwayBefore := func(awayBefore bool) bool { return awayBefore }
+
+	awayStep := step{"/away snorkling", true, "snorkling", neverError}
+	notAwayStep := step{"/away", false, "", errorIfAwayBefore}
+	backStep := step{"/back", false, "", errorIfAwayBefore}
 
 	steps := []step{awayStep, notAwayStep, backStep}
 	cases := [][]int{
@@ -42,7 +49,12 @@ func TestAwayCommands(t *testing.T) {
 			for _, s := range []step{steps[c[0]], steps[c[1]], steps[c[2]]} {
 				msg, _ := message.NewPublicMsg(s.Msg, u).ParseCommand()
 
-				cmds.Run(room, *msg)
+				awayBeforeCommand, _, _ := u.GetAway()
+
+				err := cmds.Run(room, *msg)
+				if err != nil && s.ExpectsError(awayBeforeCommand) {
+					t.Fatalf("unexpected error running the command: %+v", err)
+				}
 
 				isAway, _, awayMsg := u.GetAway()
 				if isAway != s.IsUserAway {