Vim keybindings for source edit mode

VimHandler activates in source (edit) mode only. Two modes:
- Insert: standard typing, Esc enters normal mode
- Normal: vim navigation and editing, i/a/o/O enter insert

Normal mode commands:
  h/j/k/l: cursor movement
  w/b: word forward/back
  0/$: line start/end
  gg/G: document start/end
  i/a/o/O: enter insert mode
  x: delete char
  dd: delete line
  u: undo
  Ctrl+r: redo

test/setup.ts

@@ -22,7 +22,10 @@ export function getWindow(): any {
 }
 
 export function ribbit(): any {
-    return getWindow().ribbit;
+    const w = getWindow();
+    const r = w.ribbit;
+    r.window = w;
+    return r;
 }
 
 export function resetDOM(content = 'test'): void {

test/vim.test.ts

@@ -0,0 +1,78 @@
+import { ribbit, resetDOM } from './setup';
+
+const r = ribbit();
+
+describe('VimHandler', () => {
+    beforeEach(() => resetDOM('hello world'));
+
+    it('starts in insert mode', () => {
+        const editor = new r.Editor({});
+        editor.run();
+        editor.edit();
+        expect(editor.element.classList.contains('vim-insert')).toBe(true);
+    });
+
+    it('Esc enters normal mode', () => {
+        const editor = new r.Editor({});
+        editor.run();
+        editor.edit();
+        editor.element.dispatchEvent(new r.window.KeyboardEvent('keydown', { key: 'Escape' }));
+        expect(editor.element.classList.contains('vim-normal')).toBe(true);
+        expect(editor.element.classList.contains('vim-insert')).toBe(false);
+    });
+
+    it('i returns to insert mode', () => {
+        const editor = new r.Editor({});
+        editor.run();
+        editor.edit();
+        // Enter normal mode
+        editor.element.dispatchEvent(new r.window.KeyboardEvent('keydown', { key: 'Escape' }));
+        // Back to insert
+        editor.element.dispatchEvent(new r.window.KeyboardEvent('keydown', { key: 'i' }));
+        expect(editor.element.classList.contains('vim-insert')).toBe(true);
+        expect(editor.element.classList.contains('vim-normal')).toBe(false);
+    });
+
+    it('disables toolbar in normal mode', () => {
+        const editor = new r.Editor({ autoToolbar: false });
+        editor.run();
+        editor.toolbar.render();
+        editor.edit();
+        editor.toolbar.enable();
+        editor.element.dispatchEvent(new r.window.KeyboardEvent('keydown', { key: 'Escape' }));
+        const bold = editor.toolbar.buttons.get('bold');
+        expect(bold?.element?.classList.contains('disabled')).toBe(true);
+    });
+
+    it('re-enables toolbar in insert mode', () => {
+        const editor = new r.Editor({ autoToolbar: false });
+        editor.run();
+        editor.toolbar.render();
+        editor.edit();
+        editor.element.dispatchEvent(new r.window.KeyboardEvent('keydown', { key: 'Escape' }));
+        editor.element.dispatchEvent(new r.window.KeyboardEvent('keydown', { key: 'i' }));
+        const bold = editor.toolbar.buttons.get('bold');
+        expect(bold?.element?.classList.contains('disabled')).toBe(false);
+    });
+
+    it('detaches when leaving edit mode', () => {
+        const editor = new r.Editor({});
+        editor.run();
+        editor.edit();
+        editor.element.dispatchEvent(new r.window.KeyboardEvent('keydown', { key: 'Escape' }));
+        expect(editor.element.classList.contains('vim-normal')).toBe(true);
+        editor.wysiwyg();
+        // vim classes should be gone after mode switch
+        expect(editor.element.classList.contains('vim-normal')).toBe(false);
+        expect(editor.element.classList.contains('vim-insert')).toBe(false);
+    });
+
+    it('only activates in edit mode', () => {
+        const editor = new r.Editor({});
+        editor.run();
+        editor.wysiwyg();
+        // Esc in wysiwyg should not add vim classes
+        editor.element.dispatchEvent(new r.window.KeyboardEvent('keydown', { key: 'Escape' }));
+        expect(editor.element.classList.contains('vim-normal')).toBe(false);
+    });
+});