fix: support character deletion while holding down the Shift key. (#659)

* fix: support deletion of character using [shift+backspace] command shortcut

* refactor: remove unnecessary command handler and unit test

lib/src/editor/editor_component/service/shortcuts/command/backspace_command.dart

@@ -10,7 +10,7 @@ import 'package:flutter/material.dart';
 ///
 final CommandShortcutEvent backspaceCommand = CommandShortcutEvent(
   key: 'backspace',
-  command: 'backspace',
+  command: 'backspace, shift+backspace',
   handler: _backspaceCommandHandler,
 );
 

test/new/service/shortcuts/command_shortcut_events/delete_left_character_command_test.dart

@@ -0,0 +1,239 @@
+import 'package:appflowy_editor/appflowy_editor.dart';
+import 'package:flutter/services.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+import '../../../infra/testable_editor.dart';
+
+// single | means the cursor
+// double | means the selection
+void main() async {
+  group('deletion of a character while holding down shift key - widget test',
+      () {
+    const text = 'Welcome to AppFlowy Editor 🔥!';
+    const List<LogicalKeyboardKey> keys = [
+      LogicalKeyboardKey.shift,
+      LogicalKeyboardKey.backspace,
+    ];
+    // Before
+    // |Welcome| to AppFlowy Editor 🔥!
+    // After
+    // | to AppFlowy Editor 🔥!
+    testWidgets('Delete the collapsed selection', (tester) async {
+      final editor = tester.editor
+        ..addParagraph(
+          initialText: text,
+        );
+      await editor.startTesting();
+
+      // Welcome| to AppFlowy Editor 🔥!
+      const welcome = 'Welcome';
+      final selection = Selection.single(
+        path: [0],
+        startOffset: 0,
+        endOffset: welcome.length,
+      );
+      await editor.updateSelection(selection);
+
+      for (final LogicalKeyboardKey key in keys) {
+        await simulateKeyDownEvent(key);
+        await tester.pumpAndSettle();
+      }
+
+      // the first node should be deleted.
+      expect(
+        editor.nodeAtPath([0])?.delta?.toPlainText(),
+        text.substring(welcome.length),
+      );
+
+      await editor.dispose();
+    });
+
+    // Before
+    // # Welcome to |AppFlowy Editor 🔥!
+    // * Welcome to |AppFlowy Editor 🔥!
+    //  * Welcome to AppFlowy Editor 🔥!
+    // After
+    // # Welcome to AppFlowy Editor 🔥!
+    // * Welcome to AppFlowy Editor 🔥!
+    testWidgets(
+        'Delete the collapsed selection and the first node can\'t have children',
+        (tester) async {
+      final delta = Delta()..insert(text);
+      final editor = tester.editor
+        ..addNode(headingNode(level: 1, delta: delta))
+        ..addNode(
+          bulletedListNode(
+            delta: delta,
+            children: [bulletedListNode(delta: delta)],
+          ),
+        );
+
+      await editor.startTesting();
+
+      const welcome = 'Welcome to ';
+      final selection = Selection(
+        start: Position(
+          path: [0],
+          offset: welcome.length,
+        ),
+        end: Position(
+          path: [1],
+          offset: welcome.length,
+        ),
+      );
+      await editor.updateSelection(selection);
+
+      for (final LogicalKeyboardKey key in keys) {
+        await simulateKeyDownEvent(key);
+        await tester.pumpAndSettle();
+      }
+
+      expect(
+        editor.nodeAtPath([0])?.delta?.toPlainText(),
+        text,
+      );
+
+      final bulletedNode = editor.nodeAtPath([1])!;
+      expect(bulletedNode.type, BulletedListBlockKeys.type);
+      expect(bulletedNode.delta!.toPlainText(), text);
+
+      await editor.dispose();
+    });
+
+    // Before
+    // * Welcome to |AppFlowy Editor 🔥!
+    // * Welcome to |AppFlowy Editor 🔥!
+    //  * Welcome to AppFlowy Editor 🔥!
+    // After
+    // # Welcome to AppFlowy Editor 🔥!
+    // * Welcome to AppFlowy Editor 🔥!
+    testWidgets(
+        'Delete the collapsed selection and the first node can have children',
+        (tester) async {
+      final delta = Delta()..insert(text);
+      final editor = tester.editor
+        ..addNode(bulletedListNode(delta: delta))
+        ..addNode(
+          bulletedListNode(
+            delta: delta,
+            children: [bulletedListNode(delta: delta)],
+          ),
+        );
+
+      await editor.startTesting();
+
+      const welcome = 'Welcome to ';
+      final selection = Selection(
+        start: Position(
+          path: [0],
+          offset: welcome.length,
+        ),
+        end: Position(
+          path: [1],
+          offset: welcome.length,
+        ),
+      );
+      await editor.updateSelection(selection);
+
+      for (final LogicalKeyboardKey key in keys) {
+        await simulateKeyDownEvent(key);
+        await tester.pumpAndSettle();
+      }
+
+      expect(
+        editor.nodeAtPath([0])?.delta?.toPlainText(),
+        text,
+      );
+
+      final bulletedNode = editor.nodeAtPath([0, 0])!;
+      expect(bulletedNode.type, BulletedListBlockKeys.type);
+      expect(bulletedNode.delta!.toPlainText(), text);
+
+      await editor.dispose();
+    });
+
+    // Before
+    // Welcome to AppFlowy Editor 🔥!
+    // |---|
+    // Welcome to AppFlowy Editor 🔥!
+    // After
+    // Welcome to AppFlowy Editor 🔥!
+    // |Welcome to AppFlowy Editor 🔥!
+    testWidgets('Delete the non-text node, such as divider', (tester) async {
+      final editor = tester.editor
+        ..addParagraph(initialText: text)
+        ..addNode(dividerNode())
+        ..addParagraph(initialText: text);
+
+      await editor.startTesting();
+
+      final selection = Selection.single(
+        path: [1],
+        startOffset: 0,
+        endOffset: 1,
+      );
+      await editor.updateSelection(selection);
+
+      for (final LogicalKeyboardKey key in keys) {
+        await simulateKeyDownEvent(key);
+        await tester.pumpAndSettle();
+      }
+
+      expect(
+        editor.nodeAtPath([1])?.delta?.toPlainText(),
+        text,
+      );
+      expect(
+        editor.selection,
+        Selection.collapsed(Position(path: [1])),
+      );
+
+      await editor.dispose();
+    });
+
+    testWidgets("clear text but keep the old direction", (tester) async {
+      final editor = tester.editor
+        ..addNode(
+          paragraphNode(
+            text: 'Hello',
+            textDirection: blockComponentTextDirectionLTR,
+          ),
+        )
+        ..addNode(
+          paragraphNode(
+            text: 'س',
+            textDirection: blockComponentTextDirectionAuto,
+          ),
+        );
+      await editor.startTesting();
+
+      Node node = editor.nodeAtPath([1])!;
+      expect(
+        node.selectable?.textDirection().name,
+        blockComponentTextDirectionRTL,
+      );
+
+      final selection = Selection.collapsed(
+        Position(path: [1], offset: 1),
+      );
+      await editor.updateSelection(selection);
+
+      for (final LogicalKeyboardKey key in keys) {
+        await simulateKeyDownEvent(key);
+        await tester.pumpAndSettle();
+      }
+
+      node = editor.nodeAtPath([1])!;
+      expect(
+        node.delta?.toPlainText().isEmpty,
+        true,
+      );
+      expect(
+        node.selectable?.textDirection().name,
+        blockComponentTextDirectionRTL,
+      );
+
+      await editor.dispose();
+    });
+  });
+}