Add unittests

src/InteractiveWindow/Editor/InteractiveWindow.UIThreadOnly.cs

@@ -2164,8 +2164,18 @@ private bool IsStreamSelectionInEditableBuffer(ITextSelection selection)
             {
                 Debug.Assert(selection.Mode == TextSelectionMode.Stream);
 
-                return MapToEditableBuffer(selection.AnchorPoint.Position) != null ||
-                       MapToEditableBuffer(selection.ActivePoint.Position) != null;
+                var editableBuffer = (ReadingStandardInput) ? StandardInputBuffer : CurrentLanguageBuffer;
+                var selectedSpans = selection.SelectedSpans;
+
+                foreach (var selectedSpan in selectedSpans)
+                {
+                    var spans = TextView.BufferGraph.MapDownToBuffer(selectedSpan, SpanTrackingMode.EdgeInclusive, editableBuffer);
+                    if (spans.Count > 0)
+                    {
+                        return true;
+                    }
+                }
+                return false;
             }
 
             private bool ReduceBoxSelectionToEditableBox(bool isDelete = true)

src/InteractiveWindow/EditorTest/InteractiveWindowTests.cs

@@ -756,6 +756,467 @@ public void SelectAllInHeader()
             Assert.Equal(new Span(0, fullText.Length), Window.TextView.Selection.SelectedSpans.Single().Span);
         }
 
+        [Fact]
+        public void DeleteWithOutSelectionInReadOnlyArea()
+        {
+            Submit(
+@"1",
+@"1
+");
+            Window.InsertCode("2");                                              
+
+            var caret = Window.TextView.Caret;
+
+            // with empty selection, Delete() only handles caret movement,
+            // so we can only test caret location. 
+
+            // Delete() with caret in readonly area, no-op       
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            AssertCaretVirtualPosition(1, 1);
+
+            Task.Run(() => Window.Operations.Delete()).PumpingWait();
+            AssertCaretVirtualPosition(1, 1);
+
+            // Delete() with caret in active prompt, move caret to 
+            // closest editable buffer
+            caret.MoveToNextCaretPosition();
+            AssertCaretVirtualPosition(2, 0);
+            Task.Run(() => Window.Operations.Delete()).PumpingWait();
+            AssertCaretVirtualPosition(2, 2);
+        }
+        
+        [Fact]
+        public void DeleteWithSelectionInReadonlyArea()
+        {
+            Submit(
+@"1",
+@"1
+");
+            Window.InsertCode("23");
+
+            var caret = Window.TextView.Caret;                                   
+            var selection = Window.TextView.Selection;
+
+
+            // Delete() with selection in readonly area, no-op       
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            AssertCaretVirtualPosition(1, 1);
+
+            Window.Operations.SelectAll();
+
+            Task.Run(() => Window.Operations.Delete()).PumpingWait();
+            Assert.Equal("> 1\r\n1\r\n> 23", Window.TextView.TextBuffer.CurrentSnapshot.GetText());
+
+            // Delete() with selection in active prompt, no-op
+            selection.Clear(); 
+            var start = caret.MoveToNextCaretPosition().VirtualBufferPosition;
+            caret.MoveToNextCaretPosition();
+            var end = caret.MoveToNextCaretPosition().VirtualBufferPosition;
+            AssertCaretVirtualPosition(2, 2);
+
+            selection.Select(start, end);
+
+            Task.Run(() => Window.Operations.Delete()).PumpingWait();
+            Assert.Equal("> 1\r\n1\r\n> 23", Window.TextView.TextBuffer.CurrentSnapshot.GetText());
+
+            // Delete() with selection overlaps with editable buffer, 
+            // delete editable content and move caret to closest editable location 
+            selection.Clear();       
+            caret.MoveToPreviousCaretPosition();
+            start = caret.MoveToPreviousCaretPosition().VirtualBufferPosition;
+            caret.MoveToNextCaretPosition();
+            caret.MoveToNextCaretPosition();
+            end = caret.MoveToNextCaretPosition().VirtualBufferPosition; 
+            AssertCaretVirtualPosition(2, 3);
+
+            selection.Select(start, end);
+
+            Task.Run(() => Window.Operations.Delete()).PumpingWait();
+            Assert.Equal("> 1\r\n1\r\n> 3", Window.TextView.TextBuffer.CurrentSnapshot.GetText());
+            AssertCaretVirtualPosition(2, 2);
+        }
+
+        [Fact]
+        public void BackspaceWithOutSelectionInReadOnlyArea()
+        {
+            Submit(
+@"1",
+@"1
+");
+            Window.InsertCode("int x");
+            Window.Operations.BreakLine();
+            Window.InsertCode(";");
+
+            var caret = Window.TextView.Caret;
+
+            // Backspace() with caret in readonly area, no-op
+            Window.Operations.Home(false);
+            Window.Operations.Home(false);
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            Window.Operations.Home(false);
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();  
+            AssertCaretVirtualPosition(1, 1);
+
+            Task.Run(() => Window.Operations.Backspace()).PumpingWait();
+            AssertCaretVirtualPosition(1, 1);
+            Assert.Equal("> 1\r\n1\r\n> int x\r\n> ;", Window.TextView.TextBuffer.CurrentSnapshot.GetText());
+
+            // Backspace() with caret in 2nd active prompt, move caret to 
+            // closest editable buffer then delete prvious characer (breakline)        
+            caret.MoveToNextCaretPosition();
+            Window.Operations.End(false);
+            caret.MoveToNextCaretPosition();
+            caret.MoveToNextCaretPosition();
+            AssertCaretVirtualPosition(3, 1);
+
+            Task.Run(() => Window.Operations.Backspace()).PumpingWait();
+            AssertCaretVirtualPosition(2, 7);
+            Assert.Equal("> 1\r\n1\r\n> int x;", Window.TextView.TextBuffer.CurrentSnapshot.GetText());
+        }
+
+        [Fact]
+        public void BackspaceWithSelectionInReadonlyArea()
+        {
+            Submit(
+@"1",
+@"1
+");
+            Window.InsertCode("int x");
+            Window.Operations.BreakLine();
+            Window.InsertCode(";");
+
+            var caret = Window.TextView.Caret;
+            var selection = Window.TextView.Selection;
+
+
+            // Backspace() with selection in readonly area, no-op      
+            Window.Operations.Home(false);
+            Window.Operations.Home(false);
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            Window.Operations.Home(false);
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            AssertCaretVirtualPosition(1, 1);
+
+            Window.Operations.SelectAll();
+
+            Task.Run(() => Window.Operations.Backspace()).PumpingWait();
+            Assert.Equal("> 1\r\n1\r\n> int x\r\n> ;", Window.TextView.TextBuffer.CurrentSnapshot.GetText());
+
+            // Backspace() with selection in active prompt, no-op
+            selection.Clear();
+            var start = caret.MoveToNextCaretPosition().VirtualBufferPosition;
+            caret.MoveToNextCaretPosition();
+            var end = caret.MoveToNextCaretPosition().VirtualBufferPosition;
+            AssertCaretVirtualPosition(2, 2);
+
+            selection.Select(start, end);
+
+            Task.Run(() => Window.Operations.Backspace()).PumpingWait();
+            Assert.Equal("> 1\r\n1\r\n> int x\r\n> ;", Window.TextView.TextBuffer.CurrentSnapshot.GetText());
+
+            // Backspace() with selection overlaps with editable buffer
+            selection.Clear();
+            Window.Operations.End(false);
+            start = caret.Position.VirtualBufferPosition;
+            caret.MoveToNextCaretPosition();
+            caret.MoveToNextCaretPosition();
+            end = caret.MoveToNextCaretPosition().VirtualBufferPosition; 
+            AssertCaretVirtualPosition(3, 2);
+
+            selection.Select(start, end);
+
+            Task.Run(() => Window.Operations.Backspace()).PumpingWait();
+            Assert.Equal("> 1\r\n1\r\n> int x;", Window.TextView.TextBuffer.CurrentSnapshot.GetText());
+            AssertCaretVirtualPosition(2, 7);
+        }
+
+        [Fact]
+        public void ReturnWithOutSelectionInReadOnlyArea()
+        {
+            Submit(
+@"1",
+@"1
+");
+
+            var caret = Window.TextView.Caret;      
+
+            // Return() with caret in readonly area, no-op       
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();   
+            AssertCaretVirtualPosition(1, 1);
+
+            Task.Run(() => Window.Operations.Return()).PumpingWait();
+            AssertCaretVirtualPosition(1, 1);
+
+            // Return() with caret in active prompt, move caret to 
+            // closest editable buffer first
+            caret.MoveToNextCaretPosition();
+            AssertCaretVirtualPosition(2, 0);
+
+            Task.Run(() => Window.Operations.Return()).PumpingWait();
+            AssertCaretVirtualPosition(3, 2);
+        }
+
+        [Fact]
+        public void ReturnWithSelectionInReadonlyArea()
+        {
+            Submit(
+@"1",
+@"1
+");
+            Window.InsertCode("23");
+
+            var caret = Window.TextView.Caret;
+            var selection = Window.TextView.Selection;
+
+
+            // Return() with selection in readonly area, no-op       
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            AssertCaretVirtualPosition(1, 1);
+
+            Window.Operations.SelectAll();
+
+            Task.Run(() => Window.Operations.Return()).PumpingWait();
+            Assert.Equal("> 1\r\n1\r\n> 23", Window.TextView.TextBuffer.CurrentSnapshot.GetText());
+
+            // Return() with selection in active prompt, no-op
+            selection.Clear();
+            var start = caret.MoveToNextCaretPosition().VirtualBufferPosition;
+            caret.MoveToNextCaretPosition();
+            var end = caret.MoveToNextCaretPosition().VirtualBufferPosition;
+            AssertCaretVirtualPosition(2, 2);
+
+            selection.Select(start, end);
+
+            Task.Run(() => Window.Operations.Return()).PumpingWait();
+            Assert.Equal("> 1\r\n1\r\n> 23", Window.TextView.TextBuffer.CurrentSnapshot.GetText());
+
+            // Delete() with selection overlaps with editable buffer, 
+            // delete editable content and move caret to closest editable location and insert a return
+            selection.Clear();
+            caret.MoveToPreviousCaretPosition();
+            start = caret.MoveToPreviousCaretPosition().VirtualBufferPosition;
+            caret.MoveToNextCaretPosition();
+            caret.MoveToNextCaretPosition();
+            end = caret.MoveToNextCaretPosition().VirtualBufferPosition;
+            AssertCaretVirtualPosition(2, 3);
+
+            selection.Select(start, end);
+
+            Task.Run(() => Window.Operations.Return()).PumpingWait();
+            Assert.Equal("> 1\r\n1\r\n> \r\n> 3", Window.TextView.TextBuffer.CurrentSnapshot.GetText());
+            AssertCaretVirtualPosition(3, 2);
+        }
+
+        [Fact]
+        public void CutWithOutSelectionInReadOnlyArea()
+        {
+            Submit(
+@"1",
+@"1
+");
+            Window.InsertCode("2");
+
+            var caret = Window.TextView.Caret; 
+            Clipboard.Clear();
+
+            // Cut() with caret in readonly area, no-op       
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            AssertCaretVirtualPosition(1, 1);
+
+            Task.Run(() => Window.Operations.Cut()).PumpingWait();
+            Assert.Equal("> 1\r\n1\r\n> 2", Window.TextView.TextBuffer.CurrentSnapshot.GetText());
+            AssertCaretVirtualPosition(1, 1);
+
+            VerifyClipboardData(null);
+
+            // Cut() with caret in active prompt
+            caret.MoveToNextCaretPosition();
+            AssertCaretVirtualPosition(2, 0);
+            Task.Run(() => Window.Operations.Cut()).PumpingWait();
+
+            Assert.Equal("> 1\r\n1\r\n> ", Window.TextView.TextBuffer.CurrentSnapshot.GetText());
+            AssertCaretVirtualPosition(2, 2);
+            VerifyClipboardData("2", expectedRtf: null);
+        }
+
+        [Fact]
+        public void CutWithSelectionInReadonlyArea()
+        {
+            Submit(
+@"1",
+@"1
+");
+            Window.InsertCode("23");
+
+            var caret = Window.TextView.Caret;
+            var selection = Window.TextView.Selection;
+            Clipboard.Clear();
+
+
+            // Cut() with selection in readonly area, no-op       
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            AssertCaretVirtualPosition(1, 1);
+
+            Window.Operations.SelectAll();
+
+            Task.Run(() => Window.Operations.Cut()).PumpingWait();
+            Assert.Equal("> 1\r\n1\r\n> 23", Window.TextView.TextBuffer.CurrentSnapshot.GetText());
+            VerifyClipboardData(null);
+
+            // Cut() with selection in active prompt, no-op
+            selection.Clear();
+            var start = caret.MoveToNextCaretPosition().VirtualBufferPosition;
+            caret.MoveToNextCaretPosition();
+            var end = caret.MoveToNextCaretPosition().VirtualBufferPosition;
+            AssertCaretVirtualPosition(2, 2);
+
+            selection.Select(start, end);
+
+            Task.Run(() => Window.Operations.Cut()).PumpingWait();
+            Assert.Equal("> 1\r\n1\r\n> 23", Window.TextView.TextBuffer.CurrentSnapshot.GetText());
+            VerifyClipboardData(null);
+
+            // Cut() with selection overlaps with editable buffer, 
+            // Cut editable content and move caret to closest editable location 
+            selection.Clear();
+            caret.MoveToPreviousCaretPosition();
+            start = caret.MoveToPreviousCaretPosition().VirtualBufferPosition;
+            caret.MoveToNextCaretPosition();
+            caret.MoveToNextCaretPosition();
+            end = caret.MoveToNextCaretPosition().VirtualBufferPosition;
+            AssertCaretVirtualPosition(2, 3);
+
+            selection.Select(start, end);
+
+            Task.Run(() => Window.Operations.Cut()).PumpingWait();
+            Assert.Equal("> 1\r\n1\r\n> 3", Window.TextView.TextBuffer.CurrentSnapshot.GetText());
+            AssertCaretVirtualPosition(2, 2);
+            VerifyClipboardData("2", expectedRtf: null);
+        }
+
+        [Fact]
+        public void PasteWithOutSelectionInReadOnlyArea()
+        {
+            Submit(
+@"1",
+@"1
+");
+            Window.InsertCode("2");
+
+            var caret = Window.TextView.Caret;
+
+            Clipboard.Clear();
+            Window.Operations.Home(true);
+            Window.Operations.Copy();
+            VerifyClipboardData("2", @"\ansi{\fonttbl{\f0 Consolas;}}{\colortbl;\red0\green0\blue0;\red255\green255\blue255;}\f0 \fs24 \cf1 \cb2 \highlight2 2");
+
+            // Paste() with caret in readonly area, no-op 
+            Window.TextView.Selection.Clear();      
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();  
+            AssertCaretVirtualPosition(1, 1);
+
+            Task.Run(() => Window.Operations.Paste()).PumpingWait();
+            Assert.Equal("> 1\r\n1\r\n> 2", Window.TextView.TextBuffer.CurrentSnapshot.GetText());
+            AssertCaretVirtualPosition(1, 1);
+
+            // Paste() with caret in active prompt
+            caret.MoveToNextCaretPosition();
+            AssertCaretVirtualPosition(2, 0);                                                                                                                     
+            Task.Run(() => Window.Operations.Paste()).PumpingWait();
+
+            Assert.Equal("> 1\r\n1\r\n> 22", Window.TextView.TextBuffer.CurrentSnapshot.GetText());
+            AssertCaretVirtualPosition(2, 3);            
+        }
+
+        [Fact]
+        public void PasteWithSelectionInReadonlyArea()
+        {
+            Submit(
+@"1",
+@"1
+");
+            Window.InsertCode("23");
+
+            var caret = Window.TextView.Caret;
+            var selection = Window.TextView.Selection;
+
+            Clipboard.Clear();
+            Window.Operations.Home(true);
+            Window.Operations.Copy();
+            VerifyClipboardData("23", @"\ansi{\fonttbl{\f0 Consolas;}}{\colortbl;\red0\green0\blue0;\red255\green255\blue255;}\f0 \fs24 \cf1 \cb2 \highlight2 23");
+
+
+            // Paste() with selection in readonly area, no-op  
+            selection.Clear();
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition();
+            caret.MoveToPreviousCaretPosition(); 
+            AssertCaretVirtualPosition(1, 1);
+
+            Window.Operations.SelectAll();
+
+            Task.Run(() => Window.Operations.Paste()).PumpingWait();
+            Assert.Equal("> 1\r\n1\r\n> 23", Window.TextView.TextBuffer.CurrentSnapshot.GetText());  
+
+            // Paste() with selection in active prompt, no-op
+            selection.Clear();
+            var start = caret.MoveToNextCaretPosition().VirtualBufferPosition;
+            caret.MoveToNextCaretPosition();
+            var end = caret.MoveToNextCaretPosition().VirtualBufferPosition;
+            AssertCaretVirtualPosition(2, 2);
+
+            selection.Select(start, end);
+
+            Task.Run(() => Window.Operations.Paste()).PumpingWait();
+            Assert.Equal("> 1\r\n1\r\n> 23", Window.TextView.TextBuffer.CurrentSnapshot.GetText()); 
+
+            // Paste() with selection overlaps with editable buffer, 
+            // Cut editable content, move caret to closest editable location and insert text
+            selection.Clear();
+            caret.MoveToPreviousCaretPosition();
+            start = caret.MoveToPreviousCaretPosition().VirtualBufferPosition;
+            caret.MoveToNextCaretPosition();
+            caret.MoveToNextCaretPosition();
+            end = caret.MoveToNextCaretPosition().VirtualBufferPosition;
+            AssertCaretVirtualPosition(2, 3);
+
+            selection.Select(start, end);
+
+            Task.Run(() => Window.Operations.Paste()).PumpingWait();
+            Assert.Equal("> 1\r\n1\r\n> 233", Window.TextView.TextBuffer.CurrentSnapshot.GetText());
+            AssertCaretVirtualPosition(2, 4);             
+        }
+
         private void Submit(string submission, string output)
         {
             Task.Run(() => Window.SubmitAsync(new[] { submission })).PumpingWait();

src/InteractiveWindow/EditorTest/TestInteractiveEngine.cs

@@ -57,7 +57,7 @@ public Task<ExecutionResult> ExecuteCodeAsync(string text)
 
         public string FormatClipboard()
         {
-            return "";
+            return null;
         }
 
         public void AbortExecution()