Add new reference snapshots

Author: jtpio

ui-tests/tests/notebooks/widgets.ipynb

@@ -6,15 +6,8 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "import ipywidgets as widgets"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": [
+    "import ipywidgets as widgets\n",
+    "\n",
     "widgets.IntSlider(\n",
     "    value=7,\n",
     "    min=0,\n",

ui-tests/tests/widgets.test.ts

@@ -23,14 +23,25 @@ test.describe('Widget Visual Regression', () => {
     const notebook = 'widgets.ipynb';
     await page.notebook.openByPath(`${tmpPath}/${notebook}`);
     await page.notebook.activate(notebook);
+
+    const captures = new Array<Buffer>();
+    const cellCount = await page.notebook.getCellCount();
+
+    await page.notebook.runCellByCell({
+      onAfterCellRun: async (cellIndex: number) => {
+        const cell = await page.notebook.getCellOutput(cellIndex);
+        if (cell) {
+          captures.push(await cell.screenshot());
+        }
+      },
+    });
+
     await page.notebook.runCellByCell();
     await page.notebook.save();
 
-    const cellCount = await page.notebook.getCellCount();
-    for (let c = 0; c < cellCount; ++c) {
-      const cell = await page.notebook.getCellOutput(c);
-      const image = `cell-${c}`;
-      expect(await cell.screenshot()).toMatchSnapshot(image);
+    for (let i = 0; i < cellCount; i++) {
+      const image = `cell-${i}.png`;
+      expect(captures[i]).toMatchSnapshot(image);
     }
   });
 });