test: add widget config tests (batch 1)

src/widgets/calendar/widget.test.js

@@ -0,0 +1,12 @@
+import { describe, expect, it } from "vitest";
+
+import { expectWidgetConfigShape } from "test-utils/widget-config";
+
+import widget from "./widget";
+
+describe("calendar widget config", () => {
+  it("exports a valid widget config", () => {
+    expectWidgetConfigShape(widget);
+    expect(widget.api).toBe("{url}");
+  });
+});