Fix console issues with deleting characters (#471)

src/Microsoft.Repl/Input/InputManager.cs

@@ -16,6 +16,18 @@ public class InputManager : IInputManager
         private readonly Dictionary<ConsoleKey, Dictionary<ConsoleModifiers, AsyncKeyPressHandler>> _handlers = new Dictionary<ConsoleKey, Dictionary<ConsoleModifiers, AsyncKeyPressHandler>>();
         private readonly List<char> _inputBuffer = new List<char>();
 
+        public InputManager() { }
+
+        /// <summary>
+        /// For testing purposes only
+        /// </summary>
+        internal InputManager(string initialInput, int initialPosition)
+        {
+            _inputBuffer.AddRange(initialInput);
+            CaretPosition = initialPosition;
+        }
+
+
         public bool IsOverwriteMode { get; set; }
 
         public int CaretPosition { get; private set; }
@@ -88,31 +100,35 @@ public void RemoveCurrentCharacter(IShellState state)
         {
             state = state ?? throw new ArgumentNullException(nameof(state));
 
-            if (CaretPosition == _inputBuffer.Count)
+            int caret = CaretPosition;
+            if (caret == _inputBuffer.Count)
             {
                 return;
             }
 
             List<char> update = _inputBuffer.ToList();
-            update.RemoveAt(CaretPosition);
+            update.RemoveAt(caret);
             state.ConsoleManager.IsCaretVisible = false;
             SetInput(state, update);
+            state.MoveCarets(caret - CaretPosition);
             state.ConsoleManager.IsCaretVisible = true;
         }
 
         public void RemovePreviousCharacter(IShellState state)
         {
             state = state ?? throw new ArgumentNullException(nameof(state));
 
-            if (CaretPosition == 0)
+            int caret = CaretPosition;
+            if (caret == 0)
             {
                 return;
             }
 
             List<char> update = _inputBuffer.ToList();
-            update.RemoveAt(CaretPosition - 1);
+            update.RemoveAt(caret - 1);
             state.ConsoleManager.IsCaretVisible = false;
             SetInput(state, update);
+            state.MoveCarets(caret - CaretPosition - 1);
             state.ConsoleManager.IsCaretVisible = true;
         }
 

src/Microsoft.Repl/Properties/AssemblyInfo.cs

@@ -1,4 +1,8 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System.Runtime.CompilerServices;
+
+[assembly: InternalsVisibleTo("Microsoft.Repl.Tests, PublicKey=0024000004800000940000000602000000240000525341310004000001000100b5fc90e7027f67871e773a8fde8938c81dd402ba65b9201d60593e96c492651e889cc13f1415ebb53fac1131ae0bd333c5ee6021672d9718ea31a8aebd0da0072f25d87dba6fc90ffd598ed4da35e44c398c454307e8e33b8426143daec9f596836f97c8f74750e5975c64e2189f45def46b2a2b1247adc3652bf5c308055da9")]
 [assembly: System.Diagnostics.CodeAnalysis.SuppressMessage("Design", "CA1031:Do not catch general exception types", Justification = "This is done commonly throughout the codebase to catch unexpected errors.")]
+

test/Microsoft.HttpRepl.Fakes/MockedShellState.cs

@@ -18,7 +18,7 @@ public class MockedShellState : IShellState
     {
         private readonly ShellState _shellState;
         private readonly StringBuilder _output = new StringBuilder();
-        public MockedShellState()
+        public MockedShellState(IInputManager inputManager = null)
         {
             DefaultCommandDispatcher<object> defaultCommandDispatcher = DefaultCommandDispatcher.Create(x => { }, new object());
             Mock<IConsoleManager> mockedConsoleManager = new Mock<IConsoleManager>();
@@ -28,7 +28,7 @@ public MockedShellState()
             mockedConsoleManager.Setup(x => x.Write(It.IsAny<string>())).Callback((string s) => _output.Append(s));
             mockedConsoleManager.Setup(x => x.WriteLine(It.IsAny<string>())).Callback((string s) => _output.AppendLine(s));
 
-            _shellState = new ShellState(defaultCommandDispatcher, consoleManager: mockedConsoleManager.Object);
+            _shellState = new ShellState(defaultCommandDispatcher, inputManager: inputManager, consoleManager: mockedConsoleManager.Object);
         }
 
         public string ErrorMessage { get; private set; }

test/Microsoft.Repl.Tests/InputManagerTests.cs

@@ -0,0 +1,119 @@
+using Microsoft.HttpRepl.Fakes;
+using Microsoft.Repl.Input;
+using Xunit;
+
+namespace Microsoft.Repl.Tests
+{
+    public class InputManagerTests
+    {
+        [Fact]
+        public void RemovePreviousCharacter_AtBeginning_DoesNothing()
+        {
+            // Arrange
+            string initialInput = "echo on";
+            int initialPosition = 0;
+            InputManager inputManager = new(initialInput, initialPosition);
+            MockedShellState mockedShellState = new(inputManager);
+
+            // Act
+            inputManager.RemovePreviousCharacter(mockedShellState);
+
+            // Assert
+            Assert.Equal(initialPosition, inputManager.CaretPosition);
+            Assert.Equal(initialInput, inputManager.GetCurrentBuffer());
+        }
+
+        [Fact]
+        public void RemovePreviousCharacter_AtEnd_RemovesLastCharacter()
+        {
+            // Arrange
+            string initialInput = "echo on";
+            int initialPosition = 7;
+            string expectedInput = "echo o";
+            int expectedPosition = 6;
+            InputManager inputManager = new(initialInput, initialPosition);
+            MockedShellState mockedShellState = new(inputManager);
+
+            // Act
+            inputManager.RemovePreviousCharacter(mockedShellState);
+
+            // Assert
+            Assert.Equal(expectedPosition, inputManager.CaretPosition);
+            Assert.Equal(expectedInput, inputManager.GetCurrentBuffer());
+        }
+
+        [Fact]
+        public void RemovePreviousCharacter_InMiddle_RemovesProperCharacter()
+        {
+            // Arrange
+            string initialInput = "echo on";
+            int initialPosition = 4;
+            string expectedInput = "ech on";
+            int expectedPosition = 3;
+            InputManager inputManager = new(initialInput, initialPosition);
+            MockedShellState mockedShellState = new(inputManager);
+
+            // Act
+            inputManager.RemovePreviousCharacter(mockedShellState);
+
+            // Assert
+            Assert.Equal(expectedPosition, inputManager.CaretPosition);
+            Assert.Equal(expectedInput, inputManager.GetCurrentBuffer());
+        }
+
+        [Fact]
+        public void RemoveCurrentCharacter_AtEnd_DoesNothing()
+        {
+            // Arrange
+            string initialInput = "echo on";
+            int initialPosition = 7;
+            InputManager inputManager = new(initialInput, initialPosition);
+            MockedShellState mockedShellState = new(inputManager);
+
+            // Act
+            inputManager.RemoveCurrentCharacter(mockedShellState);
+
+            // Assert
+            Assert.Equal(initialPosition, inputManager.CaretPosition);
+            Assert.Equal(initialInput, inputManager.GetCurrentBuffer());
+        }
+
+        [Fact]
+        public void RemoveCurrentCharacter_AtBeginning_RemovesFirstCharacter()
+        {
+            // Arrange
+            string initialInput = "echo on";
+            int initialPosition = 0;
+            string expectedInput = "cho on";
+            int expectedPosition = 0;
+            InputManager inputManager = new(initialInput, initialPosition);
+            MockedShellState mockedShellState = new(inputManager);
+
+            // Act
+            inputManager.RemoveCurrentCharacter(mockedShellState);
+
+            // Assert
+            Assert.Equal(expectedPosition, inputManager.CaretPosition);
+            Assert.Equal(expectedInput, inputManager.GetCurrentBuffer());
+        }
+
+        [Fact]
+        public void RemoveCurrentCharacter_InMiddle_RemovesProperCharacter()
+        {
+            // Arrange
+            string initialInput = "echo on";
+            int initialPosition = 4;
+            string expectedInput = "echoon";
+            int expectedPosition = 4;
+            InputManager inputManager = new(initialInput, initialPosition);
+            MockedShellState mockedShellState = new(inputManager);
+
+            // Act
+            inputManager.RemoveCurrentCharacter(mockedShellState);
+
+            // Assert
+            Assert.Equal(expectedPosition, inputManager.CaretPosition);
+            Assert.Equal(expectedInput, inputManager.GetCurrentBuffer());
+        }
+    }
+}