Fixes #3368. Fix unit tests to dispose properly

Terminal.Gui/View/View.cs

@@ -503,9 +503,23 @@ public virtual bool OnTitleChanging (string oldTitle, string newTitle)
  /// <returns></returns>
  public override string ToString () { return $"{GetType ().Name}({Id}){Frame}"; }
 
- /// <inheritdoc/>
+ /// <summary>Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.</summary>
+ /// <remarks>
+ /// <para>
+ /// Subviews added to this view via <see cref="Add(View)"/> have their lifetime owned by this view and <see cref="Dispose"/> will
+ /// dispose them. To prevent this, and have the creator of the Subview instance handle disposal, use <see cref="Remove"/> to remove
+ /// the subview first.
+ /// </para>
+ /// <para>
+ /// If disposing equals true, the method has been called directly or indirectly by a user's code. Managed and
+ /// unmanaged resources can be disposed. If disposing equals false, the method has been called by the runtime from
+ /// inside the finalizer, and you should not reference other objects. Only unmanaged resources can be disposed.
+ /// </para>
+ /// </remarks>
+ /// <param name="disposing"></param>
  protected override void Dispose (bool disposing)
  {
+ // BUGBUG: We should only dispose these objects if disposing == true
  LineCanvas.Dispose ();
 
  DisposeAdornments ();

Terminal.Gui/Views/TableView/TableView.cs

@@ -908,10 +908,10 @@ public override void OnDrawContent (Rectangle viewport)
  // What columns to render at what X offset in viewport
  ColumnToRender [] columnsToRender = CalculateViewport (Viewport).ToArray ();
 
- Driver.SetAttribute (GetNormalColor ());
+ Driver?.SetAttribute (GetNormalColor ());
 
  //invalidate current row (prevents scrolling around leaving old characters in the frame
- Driver.AddStr (new string (' ', Viewport.Width));
+ Driver?.AddStr (new string (' ', Viewport.Width));
 
  var line = 0;
 

UnitTests/Application/ApplicationTests.cs

@@ -40,10 +40,12 @@ public void Begin_Null_Toplevel_Throws ()
  public void Begin_Sets_Application_Top_To_Console_Size ()
  {
  Assert.Null (Application.Top);
- Application.Begin (new ());
+ Toplevel top = new ();
+ Application.Begin (top);
  Assert.Equal (new (0, 0, 80, 25), Application.Top.Frame);
  ((FakeDriver)Application.Driver).SetBufferSize (5, 5);
  Assert.Equal (new (0, 0, 5, 5), Application.Top.Frame);
+ top.Dispose ();
  }
 
  [Fact]
@@ -265,8 +267,6 @@ public void Init_Unbalanced_Throws ()
  {
  Application.Init (new FakeDriver ());
 
- Toplevel topLevel = null;
-
  Assert.Throws<InvalidOperationException> (
  () =>
  Application.InternalInit (
@@ -280,7 +280,6 @@ public void Init_Unbalanced_Throws ()
  Assert.Null (Application.Driver);
 
  // Now try the other way
- topLevel = null;
  Application.InternalInit (new FakeDriver ());
 
  Assert.Throws<InvalidOperationException> (() => Application.Init (new FakeDriver ()));
@@ -347,6 +346,7 @@ public void Internal_Properties_Correct ()
  Assert.Null (Application.MouseGrabView); // public
  Assert.Null (Application.WantContinuousButtonPressedView); // public
  Assert.False (Application.MoveToOverlappedChild (Application.Top));
+ Application.Top.Dispose ();
  }
 
  // Invoke Tests

UnitTests/Application/KeyboardTests.cs

@@ -172,6 +172,7 @@ public void EnsuresTopOnFront_CanFocus_False_By_Keyboard ()
  Assert.True (win2.CanFocus);
  Assert.True (win2.HasFocus);
  Assert.Equal ("win2", ((Window)top.Subviews [^1]).Title);
+ top.Dispose ();
  }
 
  [Fact]
@@ -224,6 +225,7 @@ public void EnsuresTopOnFront_CanFocus_True_By_Keyboard_ ()
  Assert.True (win2.CanFocus);
  Assert.False (win2.HasFocus);
  Assert.Equal ("win", ((Window)top.Subviews [^1]).Title);
+ top.Dispose ();
  }
 
  [Fact]
@@ -358,6 +360,7 @@ public void OnKeyDown_Application_KeyBinding ()
  Assert.True (view.ApplicationCommand);
  Assert.True (view.HotKeyCommand);
  Assert.False (view.FocusedCommand);
+ top.Dispose ();
  }
 
  [Fact]
@@ -385,6 +388,7 @@ public void OnKeyDown_Application_KeyBinding_Negative ()
  Assert.False (view.ApplicationCommand);
  Assert.False (view.HotKeyCommand);
  Assert.False (view.FocusedCommand);
+ top.Dispose ();
  }
 
  [Fact]
@@ -423,6 +427,7 @@ public void QuitKey_Getter_Setter ()
 
  // Reset the QuitKey to avoid throws errors on another tests
  Application.QuitKey = Key.Q.WithCtrl;
+ top.Dispose ();
  }
 
  // test Application key Bindings

UnitTests/Application/MainLoopTests.cs

@@ -640,6 +640,7 @@ public async Task InvokeLeakTest ()
  await task; // Propagate exception if any occurred
 
  Assert.Equal (numIncrements * numPasses, tbCounter);
+ top.Dispose ();
  }
 
  [Theory]
@@ -714,6 +715,7 @@ int pfour
  };
 
  Application.Run (top);
+ top.Dispose ();
 
  Assert.True (taskCompleted);
  Assert.Equal (clickMe, btn.Text);

UnitTests/Application/MouseTests.cs

@@ -130,6 +130,7 @@ bool expectedClicked
 
  Application.OnMouseEvent (mouseEvent);
  Assert.Equal (expectedClicked, clicked);
+ top.Dispose ();
  }
 
  /// <summary>
@@ -224,6 +225,7 @@ bool expectedClicked
 
  Application.OnMouseEvent (mouseEvent);
  Assert.Equal (expectedClicked, clicked);
+ top.Dispose ();
  }
 
  #endregion mouse coordinate tests
@@ -290,6 +292,7 @@ public void MouseGrabView_WithNullMouseEventView ()
  };
 
  Application.Run (top);
+ top.Dispose ();
  }
 
  [Fact]
@@ -396,6 +399,7 @@ public void View_Is_Responsible_For_Calling_UnGrabMouse_Before_Being_Disposed ()
  Application.OnMouseEvent (new () { Position = new (0, 0), Flags = MouseFlags.Button1Pressed });
  Assert.Null (Application.MouseGrabView);
  Assert.Equal (0, count);
+ top.Dispose ();
  }
  #endregion
 }

UnitTests/Dialogs/DialogTests.cs

@@ -906,8 +906,10 @@ public void Dialog_In_Window_With_Size_One_Button_Aligns ()
  };
 
  Run (dlg);
+ dlg.Dispose ();
  };
  Run (win);
+ win.Dispose ();
  }
 
  [Theory]
@@ -988,6 +990,7 @@ public void Dialog_In_Window_Without_Size_One_Button_Aligns (int height, string
  Height = Dim.Percent (85)
  };
  Run (dlg);
+ dlg.Dispose ();
  }
  else if (iterations == 1)
  {
@@ -1001,6 +1004,7 @@ public void Dialog_In_Window_Without_Size_One_Button_Aligns (int height, string
  };
 
  Run (win);
+ win.Dispose ();
  }
 
  [Fact]
@@ -1134,6 +1138,7 @@ public void Location_Default ()
  // Default location is centered, so 100 / 2 - 85 / 2 = 7
  var expected = 7;
  Assert.Equal (new (expected, expected), d.Frame.Location);
+ d.Dispose ();
  }
 
  [Fact]
@@ -1147,6 +1152,7 @@ public void Location_Not_Default ()
  // Default location is centered, so 100 / 2 - 85 / 2 = 7
  var expected = 1;
  Assert.Equal (new (expected, expected), d.Frame.Location);
+ d.Dispose ();
  }
 
  [Fact]
@@ -1170,6 +1176,7 @@ public void Location_When_Application_Top_Not_Default ()
  └───┘",
  _output
  );
+ d.Dispose ();
  }
 
  [Fact]
@@ -1263,6 +1270,7 @@ public void Location_When_Not_Application_Top_Not_Default ()
 
  ((FakeDriver)Driver).SetBufferSize (20, 10);
  Run (top);
+ top.Dispose ();
  }
 
  [Fact]
@@ -1282,14 +1290,15 @@ public void One_Button_Works ()
  int width = buttonRow.Length;
  d.SetBufferSize (buttonRow.Length, 10);
 
- (runstate, Dialog _) = RunButtonTestDialog (
+ (runstate, Dialog dlg) = RunButtonTestDialog (
  title,
  width,
  Alignment.Center,
  new Button { Text = btnText }
  );
  TestHelpers.AssertDriverContentsWithFrameAre ($"{buttonRow}", _output);
  End (runstate);
+ dlg.Dispose ();
  }
 
  [Fact]