add test for using carraige return to replace previous text

Author: amunger

src/vs/workbench/contrib/notebook/test/browser/notebookTextModel.test.ts

@@ -436,7 +436,7 @@ suite('NotebookTextModel', () => {
 		);
 	});
 
-	test('appending streaming outputs with compression', async function () {
+	test('appending streaming outputs with move cursor compression', async function () {
 
 		await withTestNotebook(
 			[
@@ -478,6 +478,48 @@ suite('NotebookTextModel', () => {
 		);
 	});
 
+	test('appending streaming outputs with carraige return compression', async function () {
+
+		await withTestNotebook(
+			[
+				['var a = 1;', 'javascript', CellKind.Code, [], {}],
+			],
+			(editor) => {
+				const textModel = editor.textModel;
+
+				textModel.applyEdits([
+					{
+						index: 0,
+						editType: CellEditType.Output,
+						append: true,
+						outputs: [{
+							outputId: 'append1',
+							outputs: [
+								{ mime: stdOutMime, data: valueBytesFromString('append 1') },
+								{ mime: stdOutMime, data: valueBytesFromString('\nappend 1') }]
+						}]
+					}], true, undefined, () => undefined, undefined, true);
+				const [output] = textModel.cells[0].outputs;
+				assert.strictEqual(output.versionId, 0, 'initial output version should be 0');
+
+				textModel.applyEdits([
+					{
+						editType: CellEditType.OutputItems,
+						append: true,
+						outputId: 'append1',
+						items: [{
+							mime: stdOutMime, data: valueBytesFromString('\rappend 2')
+						}]
+					}], true, undefined, () => undefined, undefined, true);
+				assert.strictEqual(output.versionId, 1, 'version should bump per append');
+
+				assert.strictEqual(output.outputs[0].data.toString(), 'append 1\nappend 2');
+				assert.strictEqual(output.appendedSinceVersion(0, stdOutMime), undefined,
+					'compressing outputs should clear out previous versioned output buffers');
+			}
+		);
+	});
+
 	test('appending multiple different mime streaming outputs', async function () {
 		await withTestNotebook(
 			[