test(frame-router): add tests for the current host URL modification b…

…ehavior

This behavior is somewhat inconsistent and should be re-worked in the future, but this will let us
make small improvements and bugfixes without regressing current behavior in a way that could break
existing usage.

packages/iframe-coordinator/src/specs/FrameRouter.spec.ts

@@ -0,0 +1,70 @@
+import { FrameRouterElement } from "../host";
+
+const ENV_DATA = {
+  locale: "en-us",
+  hostRootUrl: "https://example.com/root/",
+};
+
+const ENV_DATA_WITH_HASH = {
+  ...ENV_DATA,
+  hostRootUrl: "https://example.com/root/#/",
+};
+
+describe("The frame router element", () => {
+  beforeAll(() => {
+    window.customElements.define("frame-router", FrameRouterElement);
+  });
+
+  beforeEach(() => {
+    // Reset window hash state
+    window.location.hash = "";
+  });
+
+  /* NOTE: This behavior is inconsistent in practice and needs to be reworked.
+   * For now, these tests prevent regressions against the current inconsistent
+   * behavior.
+   */
+  describe("Host URL management", () => {
+    it("Removes a trailing slash on the host URL if present", () => {
+      const router = new FrameRouterElement();
+      router.clientConfig = {
+        clients: {},
+        envData: ENV_DATA,
+      };
+      //@ts-ignore
+      expect(router._envData).toEqual({
+        ...ENV_DATA,
+        hostRootUrl: "https://example.com/root",
+      });
+    });
+
+    it("Adds a fragment to the tracked host URL if one is present on window but not on the provided root URL", () => {
+      window.location.hash = "foo";
+      const router = new FrameRouterElement();
+      router.clientConfig = {
+        clients: {},
+        envData: ENV_DATA,
+      };
+      //@ts-ignore
+      expect(router._envData).toEqual({
+        ...ENV_DATA,
+        hostRootUrl: "https://example.com/root/#",
+      });
+    });
+
+    it("Does not modify the provided host URL if it and the current location have a fragment", () => {
+      window.location.hash = "foo";
+      const router = new FrameRouterElement();
+      router.clientConfig = {
+        clients: {},
+        envData: ENV_DATA_WITH_HASH,
+      };
+      //@ts-ignore
+      expect(router._envData).toEqual({
+        ...ENV_DATA_WITH_HASH,
+      });
+    });
+
+    // TODO: Test expected query behavior here
+  });
+});