test: scaffold component testing with Vitest

tests/TreeView/TreeView.test.ts

@@ -0,0 +1,40 @@
+import { render, screen } from "@testing-library/svelte";
+import { user } from "../setup-tests";
+import TreeView from "./TreeView.test.svelte";
+
+describe("TreeView", () => {
+  const getItemByName = (name: RegExp) => {
+    return screen.getByRole("treeitem", {
+      name,
+      selected: false,
+    });
+  };
+
+  const getSelectedItemByName = (name: RegExp) => {
+    return screen.getByRole("treeitem", {
+      name,
+      selected: true,
+    });
+  };
+
+  it("can select a node", async () => {
+    const consoleLog = vi.spyOn(console, "log");
+
+    render(TreeView);
+
+    const firstItem = getItemByName(/AI \/ Machine learning/);
+    expect(firstItem).toBeInTheDocument();
+
+    await user.click(firstItem);
+    expect(getSelectedItemByName(/AI \/ Machine learning/)).toBeInTheDocument();
+    expect(consoleLog).toBeCalledWith("selectedIds", [0]);
+    expect(consoleLog).toBeCalledWith("select", {
+      disabled: false,
+      expanded: false,
+      id: 0,
+      leaf: true,
+      selected: false,
+      text: "AI / Machine learning",
+    });
+  });
+});