Start adding some basic document link pinning tests

extensions/markdown-language-features/src/test/documentLinkProvider.test.ts

+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import * as assert from 'assert';
+import 'mocha';
+import * as vscode from 'vscode';
+import LinkProvider from '../features/documentLinkProvider';
+import { InMemoryDocument } from './inMemoryDocument';
+
+
+const testFileName = vscode.Uri.parse('test.md');
+
+const noopToken = new class implements vscode.CancellationToken {
+	private _onCancellationRequestedEmitter = new vscode.EventEmitter<void>();
+	public onCancellationRequested = this._onCancellationRequestedEmitter.event;
+
+	get isCancellationRequested() { return false; }
+};
+
+function getLinksForFile(fileContents: string) {
+	const doc = new InMemoryDocument(testFileName, fileContents);
+	const provider = new LinkProvider();
+	return provider.provideDocumentLinks(doc, noopToken);
+}
+
+
+suite('markdown.DocumentLinkProvider', () => {
+	test('Should not return anything for empty document', async () => {
+		const links = getLinksForFile('');
+		assert.strictEqual(links.length, 0);
+	});
+
+	test('Should not return anything for simple document without links', async () => {
+		const links = getLinksForFile('# a\nfdasfdfsafsa');
+		assert.strictEqual(links.length, 0);
+	});
+
+	test('Should should detect basic http link', async () => {
+		const links = getLinksForFile('a [b](https://example.com) c');
+		assert.strictEqual(links.length, 1);
+	});
+});
+
+

extensions/markdown-language-features/src/test/inMemoryDocument.ts

@@ -44,8 +44,12 @@ export class InMemoryDocument implements vscode.TextDocument {
 	offsetAt(_position: vscode.Position): never {
 		throw new Error('Method not implemented.');
 	}
-	positionAt(_offset: number): never {
-		throw new Error('Method not implemented.');
+	positionAt(offset: number): vscode.Position {
+		const before = this._contents.slice(0, offset);
+		const newLines = before.match(/\n/g);
+		const line = newLines ? newLines.length : 0;
+		const preCharacters = before.match(/(\n|^).*$/g);
+		return new vscode.Position(line, preCharacters ? preCharacters[0].length : 0);
 	}
 	getText(_range?: vscode.Range | undefined): string {
 		return this._contents;