Link up ready button to spectate state

osu.Game.Tests/Visual/Multiplayer/TestSceneMultiplayerSpectateButton.cs

@@ -18,6 +18,7 @@ using osu.Game.Online.Rooms;
 using osu.Game.Rulesets;
 using osu.Game.Screens.OnlinePlay.Multiplayer.Match;
 using osu.Game.Tests.Resources;
+using osu.Game.Users;
 using osuTK;
 using osuTK.Input;
 
@@ -119,6 +120,12 @@ namespace osu.Game.Tests.Visual.Multiplayer
             };
         });
 
+        [Test]
+        public void TestEnabledWhenRoomOpen()
+        {
+            assertSpectateButtonEnablement(true);
+        }
+
         [TestCase(MultiplayerUserState.Idle)]
         [TestCase(MultiplayerUserState.Ready)]
         public void TestToggleWhenIdle(MultiplayerUserState initialState)
@@ -130,6 +137,47 @@ namespace osu.Game.Tests.Visual.Multiplayer
             AddAssert("user is idle", () => Client.Room?.Users[0].State == MultiplayerUserState.Idle);
         }
 
+        [TestCase(MultiplayerRoomState.WaitingForLoad)]
+        [TestCase(MultiplayerRoomState.Playing)]
+        [TestCase(MultiplayerRoomState.Closed)]
+        public void TestDisabledDuringGameplayOrClosed(MultiplayerRoomState roomState)
+        {
+            AddStep($"change user to {roomState}", () => Client.ChangeRoomState(roomState));
+            assertSpectateButtonEnablement(false);
+        }
+
+        [Test]
+        public void TestReadyButtonDisabledWhenHostAndNoReadyUsers()
+        {
+            addClickSpectateButtonStep();
+            assertReadyButtonEnablement(false);
+        }
+
+        [Test]
+        public void TestReadyButtonEnabledWhenHostAndUsersReady()
+        {
+            AddStep("add user", () => Client.AddUser(new User { Id = 55 }));
+            AddStep("set user ready", () => Client.ChangeUserState(55, MultiplayerUserState.Ready));
+
+            addClickSpectateButtonStep();
+            assertReadyButtonEnablement(true);
+        }
+
+        [Test]
+        public void TestReadyButtonDisabledWhenNotHostAndUsersReady()
+        {
+            AddStep("add user and transfer host", () =>
+            {
+                Client.AddUser(new User { Id = 55 });
+                Client.TransferHost(55);
+            });
+
+            AddStep("set user ready", () => Client.ChangeUserState(55, MultiplayerUserState.Ready));
+
+            addClickSpectateButtonStep();
+            assertReadyButtonEnablement(false);
+        }
+
         private void addClickSpectateButtonStep() => AddStep("click spectate button", () =>
         {
             InputManager.MoveMouseTo(spectateButton);
@@ -142,6 +190,9 @@ namespace osu.Game.Tests.Visual.Multiplayer
             InputManager.Click(MouseButton.Left);
         });
 
+        private void assertSpectateButtonEnablement(bool shouldBeEnabled)
+            => AddAssert($"spectate button {(shouldBeEnabled ? "is" : "is not")} enabled", () => spectateButton.ChildrenOfType<OsuButton>().Single().Enabled.Value == shouldBeEnabled);
+
         private void assertReadyButtonEnablement(bool shouldBeEnabled)
             => AddAssert($"ready button {(shouldBeEnabled ? "is" : "is not")} enabled", () => readyButton.ChildrenOfType<OsuButton>().Single().Enabled.Value == shouldBeEnabled);
     }

osu.Game/Screens/OnlinePlay/Multiplayer/Match/MultiplayerReadyButton.cs

@@ -78,8 +78,9 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
             Debug.Assert(Room != null);
 
             int newCountReady = Room.Users.Count(u => u.State == MultiplayerUserState.Ready);
+            int newCountTotal = Room.Users.Count(u => u.State != MultiplayerUserState.Spectating);
 
-            string countText = $"({newCountReady} / {Room.Users.Count} ready)";
+            string countText = $"({newCountReady} / {newCountTotal} ready)";
 
             switch (localUser.State)
             {
@@ -88,6 +89,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
                     updateButtonColour(true);
                     break;
 
+                case MultiplayerUserState.Spectating:
                 case MultiplayerUserState.Ready:
                     if (Room?.Host?.Equals(localUser) == true)
                     {
@@ -105,6 +107,13 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
 
             button.Enabled.Value = Client.Room?.State == MultiplayerRoomState.Open && !operationInProgress.Value;
 
+            // When the local user is the host and spectating the match, the "start match" state should be enabled.
+            if (localUser.State == MultiplayerUserState.Spectating)
+            {
+                button.Enabled.Value &= Room?.Host?.Equals(localUser) == true;
+                button.Enabled.Value &= newCountReady > 0;
+            }
+
             if (newCountReady != countReady)
             {
                 countReady = newCountReady;

osu.Game/Tests/Visual/Multiplayer/TestMultiplayerClient.cs

@@ -58,6 +58,12 @@ namespace osu.Game.Tests.Visual.Multiplayer
             });
         }
 
+        public void ChangeRoomState(MultiplayerRoomState newState)
+        {
+            Debug.Assert(Room != null);
+            ((IMultiplayerClient)this).RoomStateChanged(newState);
+        }
+
         public void ChangeUserState(int userId, MultiplayerUserState newState)
         {
             Debug.Assert(Room != null);