Add unit test

Author: brophdawg11

packages/react-router/__tests__/dom/dom-export-test.tsx

@@ -0,0 +1,40 @@
+import * as React from "react";
+
+import { render, screen } from "@testing-library/react";
+import { createMemoryRouter, useParams } from "react-router";
+import { RouterProvider } from "react-router/dom";
+
+describe("react-router/dom", () => {
+  function ShowParams() {
+    return <pre data-testid="params">{JSON.stringify(useParams())}</pre>;
+  }
+
+  describe("Does not bundle react-router causing duplicate context issues", () => {
+    it("with route provider shows the url params", async () => {
+      const router = createMemoryRouter(
+        [
+          {
+            path: "/blog/:slug",
+            element: <ShowParams />,
+          },
+        ],
+        {
+          initialEntries: ["/blog/react-router"],
+        }
+      );
+
+      // When react-router was bundled in CJS scenarios, this `react-router/dom`
+      // version of `RouterProvider` caused duplicate contexts and we would not
+      // find the param values
+      render(<RouterProvider router={router} />);
+
+      expect(await screen.findByTestId("params")).toMatchInlineSnapshot(`
+      <pre
+        data-testid="params"
+      >
+        {"slug":"react-router"}
+      </pre>
+    `);
+    });
+  });
+});