coreci-chat/packages/byom/tests/validator.test.ts

/**
 * validator.test.ts — validateEndpoint (REQ-007).
 *
 * Mocks the global `fetch` to assert:
 *   - 200 with a valid chat-completion body → { ok: true }
 *   - 401 → { ok: false, error: "auth_failed" }
 *   - fetch throws (network/timeout) → { ok: false, error: "connection_failed" }
 */

import { describe, it, expect, vi, afterEach } from "vitest";
import { validateEndpoint } from "../src/validator.js";

const URL = "https://byom.example.com";
const KEY = "sk-test-key";

function jsonResponse(body: unknown, status = 200): Response {
  return new Response(JSON.stringify(body), {
    status,
    headers: { "Content-Type": "application/json" },
  });
}

afterEach(() => {
  vi.restoreAllMocks();
});

describe("validateEndpoint (REQ-007)", () => {
  it("returns ok:true on a 200 with a valid chat completion body", async () => {
    vi.stubGlobal(
      "fetch",
      vi.fn().mockResolvedValue(
        jsonResponse({
          id: "chatcmpl-1",
          choices: [{ index: 0, message: { role: "assistant", content: "pong" }, finish_reason: "stop" }],
          usage: { prompt_tokens: 1, completion_tokens: 1, total_tokens: 2 },
        }),
      ),
    );
    const res = await validateEndpoint(URL, KEY);
    expect(res.ok).toBe(true);
    expect(res.error).toBeUndefined();

    // Verify it POSTed to /v1/chat/completions with the bearer key.
    expect(fetch).toHaveBeenCalledTimes(1);
    const [calledUrl, init] = (fetch as unknown as ReturnType<typeof vi.fn>).mock.calls[0] as [
      string,
      RequestInit,
    ];
    expect(calledUrl).toBe(`${URL}/v1/chat/completions`);
    expect(init.method).toBe("POST");
    expect((init.headers as Record<string, string>).Authorization).toBe(`Bearer ${KEY}`);
  });

  it("returns auth_failed on 401", async () => {
    vi.stubGlobal(
      "fetch",
      vi.fn().mockResolvedValue(new Response("unauthorized", { status: 401 })),
    );
    const res = await validateEndpoint(URL, KEY);
    expect(res.ok).toBe(false);
    expect(res.error).toBe("auth_failed");
    expect(res.detail).toBeTruthy();
  });

  it("returns auth_failed on 403", async () => {
    vi.stubGlobal(
      "fetch",
      vi.fn().mockResolvedValue(new Response("forbidden", { status: 403 })),
    );
    const res = await validateEndpoint(URL, KEY);
    expect(res.ok).toBe(false);
    expect(res.error).toBe("auth_failed");
  });

  it("returns connection_failed when fetch throws", async () => {
    vi.stubGlobal("fetch", vi.fn().mockRejectedValue(new Error("ENOTFOUND")));
    const res = await validateEndpoint(URL, KEY);
    expect(res.ok).toBe(false);
    expect(res.error).toBe("connection_failed");
    expect(res.detail).toContain("ENOTFOUND");
  });

  it("returns connection_failed on 5xx", async () => {
    vi.stubGlobal(
      "fetch",
      vi.fn().mockResolvedValue(new Response("bad gateway", { status: 502 })),
    );
    const res = await validateEndpoint(URL, KEY);
    expect(res.ok).toBe(false);
    expect(res.error).toBe("connection_failed");
  });

  it("returns invalid_response on 200 with a non-chat-completion body", async () => {
    vi.stubGlobal(
      "fetch",
      vi.fn().mockResolvedValue(jsonResponse({ hello: "world" })),
    );
    const res = await validateEndpoint(URL, KEY);
    expect(res.ok).toBe(false);
    expect(res.error).toBe("invalid_response");
  });

  it("returns invalid_response on 200 with non-JSON body", async () => {
    vi.stubGlobal(
      "fetch",
      vi.fn().mockResolvedValue(new Response("not json", { status: 200 })),
    );
    const res = await validateEndpoint(URL, KEY);
    expect(res.ok).toBe(false);
    expect(res.error).toBe("invalid_response");
  });

  it("tolerates a configured URL that already ends in /v1", async () => {
    vi.stubGlobal(
      "fetch",
      vi.fn().mockResolvedValue(jsonResponse({ choices: [] })),
    );
    await validateEndpoint(`${URL}/v1`, KEY);
    const [calledUrl] = (fetch as unknown as ReturnType<typeof vi.fn>).mock.calls[0] as [string];
    expect(calledUrl).toBe(`${URL}/v1/chat/completions`);
  });
});