nerve/packages/workflow-utils/src/__tests__/create-llm-adapter.test.ts

import { afterEach, describe, expect, it, vi } from "vitest";

import { START, type ThreadContext } from "@uncaged/nerve-core";

import { createLlmAdapter } from "../create-llm-adapter.js";

function makeCtx(threadId: string, userContent: string): ThreadContext {
  return {
    threadId,
    start: {
      role: START,
      content: userContent,
      meta: { maxRounds: 10, threadId },
      timestamp: 1,
    },
    steps: [],
  };
}

describe("createLlmAdapter", () => {
  afterEach(() => {
    vi.unstubAllGlobals();
    vi.restoreAllMocks();
  });

  it("posts system + user (start.content) and returns assistant text", async () => {
    const fetchMock = vi.fn().mockResolvedValue({
      ok: true,
      status: 200,
      text: async () =>
        JSON.stringify({
          choices: [{ message: { content: "model reply" } }],
        }),
    });
    vi.stubGlobal("fetch", fetchMock);

    const provider = { baseUrl: "https://api.example/v1", apiKey: "k", model: "m" };
    const adapter = createLlmAdapter(provider);
    const out = await adapter(makeCtx("t1", "trigger text"), "system instructions");

    expect(out).toBe("model reply");
    expect(fetchMock).toHaveBeenCalledTimes(1);
    const [, init] = fetchMock.mock.calls[0] as [string, RequestInit];
    const body = JSON.parse(init.body as string) as {
      model: string;
      messages: Array<{ role: string; content: string }>;
    };
    expect(body.model).toBe("m");
    expect(body.messages).toEqual([
      { role: "system", content: "system instructions" },
      { role: "user", content: "trigger text" },
    ]);
  });

  it("throws on non-ok fetch response", async () => {
    const fetchMock = vi.fn().mockResolvedValue({
      ok: false,
      status: 500,
      text: async () => "Internal Server Error",
    });
    vi.stubGlobal("fetch", fetchMock);

    const provider = { baseUrl: "https://api.example/v1", apiKey: "k", model: "m" };
    const adapter = createLlmAdapter(provider);

    await expect(adapter(makeCtx("t1", "hi"), "sys")).rejects.toThrow("llm:");
  });

  it("throws on fetch network failure", async () => {
    const fetchMock = vi.fn().mockRejectedValue(new Error("ECONNREFUSED"));
    vi.stubGlobal("fetch", fetchMock);

    const provider = { baseUrl: "https://api.example/v1", apiKey: "k", model: "m" };
    const adapter = createLlmAdapter(provider);

    await expect(adapter(makeCtx("t1", "hi"), "sys")).rejects.toThrow();
  });
});