Merge pull request #3879 from BDisp/v2_3836_setupfakefriver-after-fix

Fixes #3836. SetupFakeDriver sometimes causes failure in the unit test.

Author: tig

Terminal.Gui/Application/Application.Initialization.cs

@@ -150,6 +150,7 @@ internal static void InternalInit (
         try
         {
             MainLoop = Driver!.Init ();
+            SubscribeDriverEvents ();
         }
         catch (InvalidOperationException ex)
         {
@@ -163,11 +164,6 @@ internal static void InternalInit (
                                                 );
         }
 
-        Driver.SizeChanged += Driver_SizeChanged;
-        Driver.KeyDown += Driver_KeyDown;
-        Driver.KeyUp += Driver_KeyUp;
-        Driver.MouseEvent += Driver_MouseEvent;
-
         SynchronizationContext.SetSynchronizationContext (new MainLoopSyncContext ());
 
         SupportedCultures = GetSupportedCultures ();
@@ -176,6 +172,26 @@ internal static void InternalInit (
         InitializedChanged?.Invoke (null, new (init));
     }
 
+    internal static void SubscribeDriverEvents ()
+    {
+        ArgumentNullException.ThrowIfNull (Driver);
+
+        Driver.SizeChanged += Driver_SizeChanged;
+        Driver.KeyDown += Driver_KeyDown;
+        Driver.KeyUp += Driver_KeyUp;
+        Driver.MouseEvent += Driver_MouseEvent;
+    }
+
+    internal static void UnsubscribeDriverEvents ()
+    {
+        ArgumentNullException.ThrowIfNull (Driver);
+
+        Driver.SizeChanged -= Driver_SizeChanged;
+        Driver.KeyDown -= Driver_KeyDown;
+        Driver.KeyUp -= Driver_KeyUp;
+        Driver.MouseEvent -= Driver_MouseEvent;
+    }
+
     private static void Driver_SizeChanged (object? sender, SizeChangedEventArgs e) { OnSizeChanging (e); }
     private static void Driver_KeyDown (object? sender, Key e) { RaiseKeyDownEvent (e); }
     private static void Driver_KeyUp (object? sender, Key e) { RaiseKeyUpEvent (e); }

Terminal.Gui/Application/Application.cs

@@ -177,10 +177,7 @@ internal static void ResetState (bool ignoreDisposed = false)
         // Driver stuff
         if (Driver is { })
         {
-            Driver.SizeChanged -= Driver_SizeChanged;
-            Driver.KeyDown -= Driver_KeyDown;
-            Driver.KeyUp -= Driver_KeyUp;
-            Driver.MouseEvent -= Driver_MouseEvent;
+            UnsubscribeDriverEvents ();
             Driver?.End ();
             Driver = null;
         }

UnitTests/Application/ApplicationScreenTests.cs

@@ -65,4 +65,24 @@ public void ClearContents_Called_When_Top_Frame_Changes ()
         Application.Top = null;
         Application.Shutdown ();
     }
+
+    [Fact]
+    public void Screen_Changes_OnSizeChanged_Without_Call_Application_Init ()
+    {
+        // Arrange
+        Application.ResetState (true);
+        Assert.Null (Application.Driver);
+        Application.Driver = new FakeDriver { Rows = 25, Cols = 25 };
+        Application.SubscribeDriverEvents ();
+        Assert.Equal (new (0, 0, 25, 25), Application.Screen);
+
+        // Act
+        (((FakeDriver)Application.Driver)!).SetBufferSize (120, 30);
+
+        // Assert
+        Assert.Equal (new (0, 0, 120, 30), Application.Screen);
+
+        // Cleanup
+        Application.ResetState (true);
+    }
 }

UnitTests/Application/ApplicationTests.cs

@@ -641,6 +641,12 @@ public void Screen_Size_Changes ()
         Application.Shutdown ();
     }
 
+    [Fact]
+    public void InitState_Throws_If_Driver_Is_Null ()
+    {
+        Assert.Throws<ArgumentNullException> (static () => Application.SubscribeDriverEvents ());
+    }
+
     private void Init ()
     {
         Application.Init (new FakeDriver ());

UnitTests/TestHelpers.cs

@@ -197,14 +197,9 @@ public override void After (MethodInfo methodUnderTest)
         // Turn off diagnostic flags in case some test left them on
         View.Diagnostics = ViewDiagnosticFlags.Off;
 
-        if (Application.Driver is { })
-        {
-            ((FakeDriver)Application.Driver).Rows = 25;
-            ((FakeDriver)Application.Driver).Cols = 25;
-            ((FakeDriver)Application.Driver).End ();
-        }
-
-        Application.Driver = null;
+        Application.ResetState (true);
+        Assert.Null (Application.Driver);
+        Assert.Equal (new (0, 0, 2048, 2048), Application.Screen);
         base.After (methodUnderTest);
     }
 
@@ -215,6 +210,9 @@ public override void Before (MethodInfo methodUnderTest)
         Application.ResetState (true);
         Assert.Null (Application.Driver);
         Application.Driver = new FakeDriver { Rows = 25, Cols = 25 };
+        Assert.Equal (new (0, 0, 25, 25), Application.Screen);
+        // Ensures subscribing events, at least for the SizeChanged event
+        Application.SubscribeDriverEvents ();
 
         base.Before (methodUnderTest);
     }