Merge branch 'dmishunov-editor-lite-arhitecture' into 'master'

Refactoring Editor Lite's architecture

See merge request gitlab-org/gitlab!40257

app/assets/javascripts/blob/utils.js

 import Editor from '~/editor/editor_lite';
 
 export function initEditorLite({ el, ...args }) {
-  if (!el) {
-    throw new Error(`"el" parameter is required to initialize Editor`);
-  }
   const editor = new Editor({
     scrollbar: {
       alwaysConsumeMouseWheel: false,

app/assets/javascripts/editor/constants.js

+import { __ } from '~/locale';
+
+export const EDITOR_LITE_INSTANCE_ERROR_NO_EL = __(
+  '"el" parameter is required for createInstance()',
+);
+
+export const URI_PREFIX = 'gitlab';

app/assets/javascripts/editor/editor_lite.js

@@ -5,13 +5,14 @@ import { defaultEditorOptions } from '~/ide/lib/editor_options';
 import { registerLanguages } from '~/ide/utils';
 import { joinPaths } from '~/lib/utils/url_utility';
 import { clearDomElement } from './utils';
+import { EDITOR_LITE_INSTANCE_ERROR_NO_EL, URI_PREFIX } from './constants';
 
 export default class Editor {
   constructor(options = {}) {
     this.editorEl = null;
     this.blobContent = '';
     this.blobPath = '';
-    this.instance = null;
+    this.instances = [];
     this.model = null;
     this.options = {
       extraEditorClassName: 'gl-editor-lite',
@@ -40,31 +41,51 @@ export default class Editor {
    * @param {string} options.blobContent The content to initialize the monacoEditor.
    * @param {string} options.blobGlobalId This is used to help globally identify monaco instances that are created with the same blobPath.
    */
-  createInstance({ el = undefined, blobPath = '', blobContent = '', blobGlobalId = '' } = {}) {
-    if (!el) return;
+  createInstance({
+    el = undefined,
+    blobPath = '',
+    blobContent = '',
+    blobGlobalId = '',
+    ...instanceOptions
+  } = {}) {
+    if (!el) {
+      throw new Error(EDITOR_LITE_INSTANCE_ERROR_NO_EL);
+    }
     this.editorEl = el;
     this.blobContent = blobContent;
     this.blobPath = blobPath;
 
     clearDomElement(this.editorEl);
 
-    const uriFilePath = joinPaths('gitlab', blobGlobalId, blobPath);
+    const uriFilePath = joinPaths(URI_PREFIX, blobGlobalId, blobPath);
 
-    this.model = monacoEditor.createModel(this.blobContent, undefined, Uri.file(uriFilePath));
+    const model = monacoEditor.createModel(this.blobContent, undefined, Uri.file(uriFilePath));
 
     monacoEditor.onDidCreateEditor(this.renderEditor.bind(this));
 
-    this.instance = monacoEditor.create(this.editorEl, this.options);
-    this.instance.setModel(this.model);
+    const instance = monacoEditor.create(this.editorEl, {
+      ...this.options,
+      ...instanceOptions,
+    });
+    instance.setModel(model);
+    instance.onDidDispose(() => {
+      const index = this.instances.findIndex(inst => inst === instance);
+      this.instances.splice(index, 1);
+      model.dispose();
+    });
+
+    // Reference to the model on the editor level will go away in
+    // https://gitlab.com/gitlab-org/gitlab/-/issues/241023
+    // After that, the references to the model will be routed through
+    // instance exclusively
+    this.model = model;
+
+    this.instances.push(instance);
+    return instance;
   }
 
   dispose() {
-    if (this.model) {
-      this.model.dispose();
-      this.model = null;
-    }
-
-    return this.instance && this.instance.dispose();
+    this.instances.forEach(instance => instance.dispose());
   }
 
   renderEditor() {
@@ -86,28 +107,52 @@ export default class Editor {
     monacoEditor.setModelLanguage(this.model, id);
   }
 
+  /**
+   * @deprecated do not use .getValue() directly on the editor.
+   * This proxy-method will be removed in https://gitlab.com/gitlab-org/gitlab/-/issues/241025
+   * Rather use it on the exact instance
+   */
   getValue() {
-    return this.instance.getValue();
+    return this.instances[0].getValue();
   }
 
+  /**
+   * @deprecated do not use .setValue() directly on the editor.
+   * This proxy-method will be removed in https://gitlab.com/gitlab-org/gitlab/-/issues/241025
+   * Rather use it on the exact instance
+   */
   setValue(val) {
-    this.instance.setValue(val);
+    this.instances[0].setValue(val);
   }
 
+  /**
+   * @deprecated do not use .focus() directly on the editor.
+   * This proxy-method will be removed in https://gitlab.com/gitlab-org/gitlab/-/issues/241025
+   * Rather use it on the exact instance
+   */
   focus() {
-    this.instance.focus();
+    this.instances[0].focus();
   }
 
-  navigateFileStart() {
-    this.instance.setPosition(new Position(1, 1));
+  /**
+   * @deprecated do not use .updateOptions() directly on the editor.
+   * This proxy-method will be removed in https://gitlab.com/gitlab-org/gitlab/-/issues/241025
+   * Rather use it on the exact instance
+   */
+  updateOptions(options = {}) {
+    this.instances[0].updateOptions(options);
   }
 
-  updateOptions(options = {}) {
-    this.instance.updateOptions(options);
+  navigateFileStart() {
+    this.instances[0].setPosition(new Position(1, 1));
   }
 
-  use(exts = []) {
+  use(exts = [], instance = null) {
     const extensions = Array.isArray(exts) ? exts : [exts];
-    Object.assign(this, ...extensions);
+    if (instance) {
+      Object.assign(instance, ...extensions);
+    } else {
+      this.instances.forEach(inst => Object.assign(inst, ...extensions));
+    }
   }
 }

app/assets/javascripts/editor/editor_markdown_ext.js

 export default {
   getSelectedText(selection = this.getSelection()) {
     const { startLineNumber, endLineNumber, startColumn, endColumn } = selection;
-    const valArray = this.instance.getValue().split('\n');
+    const valArray = this.getValue().split('\n');
     let text = '';
     if (startLineNumber === endLineNumber) {
       text = valArray[startLineNumber - 1].slice(startColumn - 1, endColumn - 1);
@@ -20,20 +20,16 @@ export default {
     return text;
   },
 
-  getSelection() {
-    return this.instance.getSelection();
-  },
-
   replaceSelectedText(text, select = undefined) {
     const forceMoveMarkers = !select;
-    this.instance.executeEdits('', [{ range: this.getSelection(), text, forceMoveMarkers }]);
+    this.executeEdits('', [{ range: this.getSelection(), text, forceMoveMarkers }]);
   },
 
   moveCursor(dx = 0, dy = 0) {
-    const pos = this.instance.getPosition();
+    const pos = this.getPosition();
     pos.column += dx;
     pos.lineNumber += dy;
-    this.instance.setPosition(pos);
+    this.setPosition(pos);
   },
 
   /**
@@ -94,6 +90,6 @@ export default {
       .setStartPosition(newStartLineNumber, newStartColumn)
       .setEndPosition(newEndLineNumber, newEndColumn);
 
-    this.instance.setSelection(newSelection);
+    this.setSelection(newSelection);
   },
 };

locale/gitlab.pot

@@ -71,6 +71,9 @@ msgstr ""
 msgid "\"%{path}\" did not exist on \"%{ref}\""
 msgstr ""
 
+msgid "\"el\" parameter is required for createInstance()"
+msgstr ""
+
 msgid "%d Scanned URL"
 msgid_plural "%d Scanned URLs"
 msgstr[0] ""

spec/frontend/editor/editor_lite_spec.js

 import { editor as monacoEditor, languages as monacoLanguages, Uri } from 'monaco-editor';
 import Editor from '~/editor/editor_lite';
 import { DEFAULT_THEME, themes } from '~/ide/lib/themes';
-
-const URI_PREFIX = 'gitlab';
+import { EDITOR_LITE_INSTANCE_ERROR_NO_EL, URI_PREFIX } from '~/editor/constants';
 
 describe('Base editor', () => {
   let editorEl;
@@ -28,8 +27,8 @@ describe('Base editor', () => {
   it('initializes Editor with basic properties', () => {
     expect(editor).toBeDefined();
     expect(editor.editorEl).toBe(null);
-    expect(editor.blobContent).toEqual('');
-    expect(editor.blobPath).toEqual('');
+    expect(editor.blobContent).toBe('');
+    expect(editor.blobPath).toBe('');
   });
 
   it('removes `editor-loading` data attribute from the target DOM element', () => {
@@ -51,15 +50,18 @@ describe('Base editor', () => {
       instanceSpy = jest.spyOn(monacoEditor, 'create').mockImplementation(() => ({
         setModel,
         dispose,
+        onDidDispose: jest.fn(),
       }));
     });
 
-    it('does nothing if no dom element is supplied', () => {
-      editor.createInstance();
+    it('throws an error if no dom element is supplied', () => {
+      expect(() => {
+        editor.createInstance();
+      }).toThrow(EDITOR_LITE_INSTANCE_ERROR_NO_EL);
 
       expect(editor.editorEl).toBe(null);
-      expect(editor.blobContent).toEqual('');
-      expect(editor.blobPath).toEqual('');
+      expect(editor.blobContent).toBe('');
+      expect(editor.blobPath).toBe('');
 
       expect(modelSpy).not.toHaveBeenCalled();
       expect(instanceSpy).not.toHaveBeenCalled();
@@ -89,15 +91,123 @@ describe('Base editor', () => {
         createUri(blobGlobalId, blobPath),
       );
     });
+
+    it('initializes instance with passed properties', () => {
+      editor.createInstance({
+        el: editorEl,
+        blobContent,
+        blobPath,
+      });
+      expect(editor.editorEl).toBe(editorEl);
+      expect(editor.blobContent).toBe(blobContent);
+      expect(editor.blobPath).toBe(blobPath);
+    });
+
+    it('disposes instance when the editor is disposed', () => {
+      editor.createInstance({ el: editorEl, blobPath, blobContent, blobGlobalId });
+
+      expect(dispose).not.toHaveBeenCalled();
+
+      editor.dispose();
+
+      expect(dispose).toHaveBeenCalled();
+    });
+  });
+
+  describe('multiple instances', () => {
+    let instanceSpy;
+    let inst1Args;
+    let inst2Args;
+    let editorEl1;
+    let editorEl2;
+    let inst1;
+    let inst2;
+    const readOnlyIndex = '68'; // readOnly option has the internal index of 68 in the editor's options
+
+    beforeEach(() => {
+      setFixtures('<div id="editor1"></div><div id="editor2"></div>');
+      editorEl1 = document.getElementById('editor1');
+      editorEl2 = document.getElementById('editor2');
+      inst1Args = {
+        el: editorEl1,
+        blobGlobalId,
+      };
+      inst2Args = {
+        el: editorEl2,
+        blobContent,
+        blobPath,
+        blobGlobalId,
+      };
+
+      editor = new Editor();
+      instanceSpy = jest.spyOn(monacoEditor, 'create');
+    });
+
+    afterEach(() => {
+      editor.dispose();
+    });
+
+    it('can initialize several instances of the same editor', () => {
+      editor.createInstance(inst1Args);
+      expect(editor.editorEl).toBe(editorEl1);
+      expect(editor.instances).toHaveLength(1);
+
+      editor.createInstance(inst2Args);
+      expect(editor.editorEl).toBe(editorEl2);
+
+      expect(instanceSpy).toHaveBeenCalledTimes(2);
+      expect(editor.instances).toHaveLength(2);
+    });
+
+    it('shares global editor options among all instances', () => {
+      editor = new Editor({
+        readOnly: true,
+      });
+
+      inst1 = editor.createInstance(inst1Args);
+      expect(inst1.getOption(readOnlyIndex)).toBe(true);
+
+      inst2 = editor.createInstance(inst2Args);
+      expect(inst2.getOption(readOnlyIndex)).toBe(true);
+    });
+
+    it('allows overriding editor options on the instance level', () => {
+      editor = new Editor({
+        readOnly: true,
+      });
+      inst1 = editor.createInstance({
+        ...inst1Args,
+        readOnly: false,
+      });
+
+      expect(inst1.getOption(readOnlyIndex)).toBe(false);
+    });
+
+    it('disposes instances and relevant models independently from each other', () => {
+      inst1 = editor.createInstance(inst1Args);
+      inst2 = editor.createInstance(inst2Args);
+
+      expect(inst1.getModel()).not.toBe(null);
+      expect(inst2.getModel()).not.toBe(null);
+      expect(editor.instances).toHaveLength(2);
+      expect(monacoEditor.getModels()).toHaveLength(2);
+
+      inst1.dispose();
+      expect(inst1.getModel()).toBe(null);
+      expect(inst2.getModel()).not.toBe(null);
+      expect(editor.instances).toHaveLength(1);
+      expect(monacoEditor.getModels()).toHaveLength(1);
+    });
   });
 
   describe('implementation', () => {
+    let instance;
     beforeEach(() => {
-      editor.createInstance({ el: editorEl, blobPath, blobContent });
+      instance = editor.createInstance({ el: editorEl, blobPath, blobContent });
     });
 
     it('correctly proxies value from the model', () => {
-      expect(editor.getValue()).toEqual(blobContent);
+      expect(instance.getValue()).toBe(blobContent);
     });
 
     it('is capable of changing the language of the model', () => {
@@ -108,10 +218,10 @@ describe('Base editor', () => {
 
       const blobRenamedPath = 'test.js';
 
-      expect(editor.model.getLanguageIdentifier().language).toEqual('markdown');
+      expect(editor.model.getLanguageIdentifier().language).toBe('markdown');
       editor.updateModelLanguage(blobRenamedPath);
 
-      expect(editor.model.getLanguageIdentifier().language).toEqual('javascript');
+      expect(editor.model.getLanguageIdentifier().language).toBe('javascript');
     });
 
     it('falls back to plaintext if there is no language associated with an extension', () => {
@@ -121,11 +231,12 @@ describe('Base editor', () => {
       editor.updateModelLanguage(blobRenamedPath);
 
       expect(spy).not.toHaveBeenCalled();
-      expect(editor.model.getLanguageIdentifier().language).toEqual('plaintext');
+      expect(editor.model.getLanguageIdentifier().language).toBe('plaintext');
     });
   });
 
   describe('extensions', () => {
+    let instance;
     const foo1 = jest.fn();
     const foo2 = jest.fn();
     const bar = jest.fn();
@@ -139,14 +250,14 @@ describe('Base editor', () => {
       foo: foo2,
     };
     beforeEach(() => {
-      editor.createInstance({ el: editorEl, blobPath, blobContent });
+      instance = editor.createInstance({ el: editorEl, blobPath, blobContent });
     });
 
     it('is extensible with the extensions', () => {
-      expect(editor.foo).toBeUndefined();
+      expect(instance.foo).toBeUndefined();
 
       editor.use(MyExt1);
-      expect(editor.foo).toEqual(foo1);
+      expect(instance.foo).toEqual(foo1);
     });
 
     it('does not fail if no extensions supplied', () => {
@@ -157,18 +268,18 @@ describe('Base editor', () => {
     });
 
     it('is extensible with multiple extensions', () => {
-      expect(editor.foo).toBeUndefined();
-      expect(editor.bar).toBeUndefined();
+      expect(instance.foo).toBeUndefined();
+      expect(instance.bar).toBeUndefined();
 
       editor.use([MyExt1, MyExt2]);
 
-      expect(editor.foo).toEqual(foo1);
-      expect(editor.bar).toEqual(bar);
+      expect(instance.foo).toEqual(foo1);
+      expect(instance.bar).toEqual(bar);
     });
 
     it('uses the last definition of a method in case of an overlap', () => {
       editor.use([MyExt1, MyExt2, MyExt3]);
-      expect(editor).toEqual(
+      expect(instance).toEqual(
         expect.objectContaining({
           foo: foo2,
           bar,
@@ -179,15 +290,48 @@ describe('Base editor', () => {
     it('correctly resolves references withing extensions', () => {
       const FunctionExt = {
         inst() {
-          return this.instance;
+          return this;
         },
         mod() {
-          return this.model;
+          return this.getModel();
         },
       };
       editor.use(FunctionExt);
-      expect(editor.inst()).toEqual(editor.instance);
-      expect(editor.mod()).toEqual(editor.model);
+      expect(instance.inst()).toEqual(editor.instances[0]);
+      expect(instance.mod()).toEqual(editor.model);
+    });
+
+    describe('multiple instances', () => {
+      let inst1;
+      let inst2;
+      let editorEl1;
+      let editorEl2;
+
+      beforeEach(() => {
+        setFixtures('<div id="editor1"></div><div id="editor2"></div>');
+        editorEl1 = document.getElementById('editor1');
+        editorEl2 = document.getElementById('editor2');
+        inst1 = editor.createInstance({ el: editorEl1, blobPath: `foo-${blobPath}` });
+        inst2 = editor.createInstance({ el: editorEl2, blobPath: `bar-${blobPath}` });
+      });
+
+      afterEach(() => {
+        editor.dispose();
+        editorEl1.remove();
+        editorEl2.remove();
+      });
+
+      it('extends all instances if no specific instance is passed', () => {
+        editor.use(MyExt1);
+        expect(inst1.foo).toEqual(foo1);
+        expect(inst2.foo).toEqual(foo1);
+      });
+
+      it('extends specific instance if it has been passed', () => {
+        editor.use(MyExt1, inst2);
+        expect(inst1.foo).toBeUndefined();
+        expect(inst2.foo).toEqual(foo1);
+      });
     });
   });
 

spec/frontend/editor/editor_markdown_ext_spec.js

@@ -4,6 +4,7 @@ import EditorMarkdownExtension from '~/editor/editor_markdown_ext';
 
 describe('Markdown Extension for Editor Lite', () => {
   let editor;
+  let instance;
   let editorEl;
   const firstLine = 'This is a';
   const secondLine = 'multiline';
@@ -13,19 +14,19 @@ describe('Markdown Extension for Editor Lite', () => {
 
   const setSelection = (startLineNumber = 1, startColumn = 1, endLineNumber = 1, endColumn = 1) => {
     const selection = new Range(startLineNumber, startColumn, endLineNumber, endColumn);
-    editor.instance.setSelection(selection);
+    instance.setSelection(selection);
   };
   const selectSecondString = () => setSelection(2, 1, 2, secondLine.length + 1); // select the whole second line
   const selectSecondAndThirdLines = () => setSelection(2, 1, 3, thirdLine.length + 1); // select second and third lines
 
-  const selectionToString = () => editor.instance.getSelection().toString();
-  const positionToString = () => editor.instance.getPosition().toString();
+  const selectionToString = () => instance.getSelection().toString();
+  const positionToString = () => instance.getPosition().toString();
 
   beforeEach(() => {
     setFixtures('<div id="editor" data-editor-loading></div>');
     editorEl = document.getElementById('editor');
     editor = new EditorLite();
-    editor.createInstance({
+    instance = editor.createInstance({
       el: editorEl,
       blobPath: filePath,
       blobContent: text,
@@ -34,17 +35,16 @@ describe('Markdown Extension for Editor Lite', () => {
   });
 
   afterEach(() => {
-    editor.instance.dispose();
     editor.model.dispose();
     editorEl.remove();
   });
 
   describe('getSelectedText', () => {
     it('does not fail if there is no selection and returns the empty string', () => {
-      jest.spyOn(editor.instance, 'getSelection');
-      const resText = editor.getSelectedText();
+      jest.spyOn(instance, 'getSelection');
+      const resText = instance.getSelectedText();
 
-      expect(editor.instance.getSelection).toHaveBeenCalled();
+      expect(instance.getSelection).toHaveBeenCalled();
       expect(resText).toBe('');
     });
 
@@ -56,7 +56,7 @@ describe('Markdown Extension for Editor Lite', () => {
     `('correctly returns selected text for $description', ({ selection, expectedString }) => {
       setSelection(...selection);
 
-      const resText = editor.getSelectedText();
+      const resText = instance.getSelectedText();
 
       expect(resText).toBe(expectedString);
     });
@@ -65,7 +65,7 @@ describe('Markdown Extension for Editor Lite', () => {
       selectSecondString();
       const firstLineSelection = new Range(1, 1, 1, firstLine.length + 1);
 
-      const resText = editor.getSelectedText(firstLineSelection);
+      const resText = instance.getSelectedText(firstLineSelection);
 
       expect(resText).toBe(firstLine);
     });
@@ -76,25 +76,25 @@ describe('Markdown Extension for Editor Lite', () => {
 
     it('replaces selected text with the supplied one', () => {
       selectSecondString();
-      editor.replaceSelectedText(expectedStr);
+      instance.replaceSelectedText(expectedStr);
 
       expect(editor.getValue()).toBe(`${firstLine}\n${expectedStr}\n${thirdLine}`);
     });
 
     it('prepends the supplied text if no text is selected', () => {
-      editor.replaceSelectedText(expectedStr);
+      instance.replaceSelectedText(expectedStr);
       expect(editor.getValue()).toBe(`${expectedStr}${firstLine}\n${secondLine}\n${thirdLine}`);
     });
 
     it('replaces selection with empty string if no text is supplied', () => {
       selectSecondString();
-      editor.replaceSelectedText();
+      instance.replaceSelectedText();
       expect(editor.getValue()).toBe(`${firstLine}\n\n${thirdLine}`);
     });
 
     it('puts cursor at the end of the new string and collapses selection by default', () => {
       selectSecondString();
-      editor.replaceSelectedText(expectedStr);
+      instance.replaceSelectedText(expectedStr);
 
       expect(positionToString()).toBe(`(2,${expectedStr.length + 1})`);
       expect(selectionToString()).toBe(
@@ -106,7 +106,7 @@ describe('Markdown Extension for Editor Lite', () => {
       const select = 'url';
       const complexReplacementString = `[${secondLine}](${select})`;
       selectSecondString();
-      editor.replaceSelectedText(complexReplacementString, select);
+      instance.replaceSelectedText(complexReplacementString, select);
 
       expect(positionToString()).toBe(`(2,${complexReplacementString.length + 1})`);
       expect(selectionToString()).toBe(`[2,1 -> 2,${complexReplacementString.length + 1}]`);
@@ -116,7 +116,7 @@ describe('Markdown Extension for Editor Lite', () => {
   describe('moveCursor', () => {
     const setPosition = endCol => {
       const currentPos = new Position(2, endCol);
-      editor.instance.setPosition(currentPos);
+      instance.setPosition(currentPos);
     };
 
     it.each`
@@ -136,9 +136,9 @@ describe('Markdown Extension for Editor Lite', () => {
       ({ startColumn, shift, endPosition }) => {
         setPosition(startColumn);
         if (Array.isArray(shift)) {
-          editor.moveCursor(...shift);
+          instance.moveCursor(...shift);
         } else {
-          editor.moveCursor(shift);
+          instance.moveCursor(shift);
         }
         expect(positionToString()).toBe(endPosition);
       },
@@ -153,18 +153,18 @@ describe('Markdown Extension for Editor Lite', () => {
 
       expect(selectionToString()).toBe(`[2,1 -> 3,${thirdLine.length + 1}]`);
 
-      editor.selectWithinSelection(toSelect, selectedText);
+      instance.selectWithinSelection(toSelect, selectedText);
       expect(selectionToString()).toBe(`[3,1 -> 3,${toSelect.length + 1}]`);
     });
 
     it('does not fail when only `toSelect` is supplied and fetches the text from selection', () => {
-      jest.spyOn(editor, 'getSelectedText');
+      jest.spyOn(instance, 'getSelectedText');
       const toSelect = 'string';
       selectSecondAndThirdLines();
 
-      editor.selectWithinSelection(toSelect);
+      instance.selectWithinSelection(toSelect);
 
-      expect(editor.getSelectedText).toHaveBeenCalled();
+      expect(instance.getSelectedText).toHaveBeenCalled();
       expect(selectionToString()).toBe(`[3,1 -> 3,${toSelect.length + 1}]`);
     });
 
@@ -176,7 +176,7 @@ describe('Markdown Extension for Editor Lite', () => {
       expect(positionToString()).toBe(expectedPos);
       expect(selectionToString()).toBe(expectedSelection);
 
-      editor.selectWithinSelection();
+      instance.selectWithinSelection();
 
       expect(positionToString()).toBe(expectedPos);
       expect(selectionToString()).toBe(expectedSelection);
@@ -190,12 +190,12 @@ describe('Markdown Extension for Editor Lite', () => {
       expect(positionToString()).toBe(expectedPos);
       expect(selectionToString()).toBe(expectedSelection);
 
-      editor.selectWithinSelection(toSelect);
+      instance.selectWithinSelection(toSelect);
 
       expect(positionToString()).toBe(expectedPos);
       expect(selectionToString()).toBe(expectedSelection);
 
-      editor.selectWithinSelection();
+      instance.selectWithinSelection();
 
       expect(positionToString()).toBe(expectedPos);
       expect(selectionToString()).toBe(expectedSelection);