feat: add extensive test suite

app/api/chat/handler.test.ts

@@ -0,0 +1,67 @@
+import { describe, expect, mock, test } from "bun:test";
+import { createChatHandler } from "./handler";
+
+const request = () => new Request("https://example.com/api/chat");
+
+describe("chat handler", () => {
+  test("fetches the live endpoint without caching and redirects to popout chat", async () => {
+    const fetch = mock((_input: RequestInfo | URL, _init?: RequestInit) =>
+      Promise.resolve(
+        Response.json({ url: "https://youtube.com/watch?v=abc_123&feature=x" }),
+      ),
+    );
+
+    const response = await createChatHandler({ fetch })(request());
+
+    expect(fetch).toHaveBeenCalledWith("https://buzz.sudloh.com/api/live", {
+      cache: "no-store",
+    });
+    expect(response.status).toBe(307);
+    expect(response.headers.get("location")).toBe(
+      "https://studio.youtube.com/live_chat?is_popout=1&v=abc_123",
+    );
+  });
+
+  test("returns 502 when the live endpoint fails", async () => {
+    const handler = createChatHandler({
+      fetch: mock(() => Promise.resolve(new Response(null, { status: 500 }))),
+    });
+    const response = await handler(request());
+    expect(response.status).toBe(502);
+    expect(await response.text()).toBe("Failed to get live stream.");
+  });
+
+  test("returns 404 when there is no live stream", async () => {
+    const handler = createChatHandler({
+      fetch: mock(() => Promise.resolve(Response.json("none"))),
+    });
+    const response = await handler(request());
+    expect(response.status).toBe(404);
+    expect(await response.text()).toContain("No live stream");
+  });
+
+  test.each([
+    { url: "https://youtube.com/watch?feature=x" },
+    { url: "not a url" },
+  ])("returns 502 for a live URL without a usable video id", async (live) => {
+    const handler = createChatHandler({
+      fetch: mock(() => Promise.resolve(Response.json(live))),
+    });
+    const response = await handler(request());
+    expect(response.status).toBe(502);
+    expect(await response.text()).toContain("video id was not found");
+  });
+
+  test("encodes the video id in the redirect URL", async () => {
+    const handler = createChatHandler({
+      fetch: mock(() =>
+        Promise.resolve(
+          Response.json({ url: "https://youtube.com/watch?v=a%26b" }),
+        ),
+      ),
+    });
+    expect((await handler(request())).headers.get("location")).toEndWith(
+      "v=a%26b",
+    );
+  });
+});