confidence-engine/tests/app/api/current-understanding-synthesis-route.test.js

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

// ── Mock domain seam and provider at module level ───────────

const mockSynthesize = vi.fn();

vi.mock("@/lib/graph/current-understanding-synthesis.js", () => ({
  synthesizeCurrentUnderstanding: (...args) => mockSynthesize(...args),
}));

vi.mock("@/lib/llm/provider.js", () => ({
  getProvider: () => ({}),
}));

// ── Helpers ─────────────────────────────────────────────────

function makeValidGraph() {
  return {
    centralStatement: "Test situation",
    nodes: [{ id: "n1", proposition: "Node prop" }],
    edges: [],
  };
}

function makeRequest(body) {
  return new Request("http://localhost/api/cases/synthesis", {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify(body),
  });
}

// ── Route tests — valid POST ────────────────────────────────

describe("POST /api/cases/synthesis — valid request", () => {
  beforeEach(() => mockSynthesize.mockClear());

  it("invokes synthesis domain seam with situationGraph + findings", async () => {
    mockSynthesize.mockResolvedValue({ currentUnderstanding: "Synthesized result" });
    const { POST } = await import("@/app/api/cases/synthesis/route.js");
    const res = await POST(makeRequest({ situationGraph: makeValidGraph(), findings: [] }));

    expect(res.status).toBe(200);
    const data = await res.json();
    expect(data.success).toBe(true);
    expect(data.currentUnderstanding).toBe("Synthesized result");
    expect(mockSynthesize).toHaveBeenCalledTimes(1);
  });

  it("returns narrative result on success", async () => {
    mockSynthesize.mockResolvedValue({ currentUnderstanding: "The revenue dropped because of X and Y." });
    const { POST } = await import("@/app/api/cases/synthesis/route.js");
    const res = await POST(makeRequest({ situationGraph: makeValidGraph() }));

    expect(res.status).toBe(200);
    const data = await res.json();
    expect(data.success).toBe(true);
    expect(typeof data.currentUnderstanding).toBe("string");
    expect(data.currentUnderstanding.length).toBeGreaterThan(0);
  });

  it("passes findings to domain seam for eligibility filtering", async () => {
    mockSynthesize.mockResolvedValue({ currentUnderstanding: "OK" });
    const findings = [
      { id: "f1", proposition: "agree finding", userDisposition: "agree", evaluation: "considered" },
      { id: "f2", proposition: "null finding", userDisposition: null, evaluation: "considered" },
      { id: "f3", proposition: "not_quite finding", userDisposition: "not_quite", evaluation: "considered" },
    ];

    const { POST } = await import("@/app/api/cases/synthesis/route.js");
    await POST(makeRequest({ situationGraph: makeValidGraph(), findings }));

    expect(mockSynthesize).toHaveBeenCalledTimes(1);
    expect(mockSynthesize.mock.calls[0][0].findings).toHaveLength(3);
  });
});

// ── Route tests — error handling ────────────────────────────

describe("POST /api/cases/synthesis — error cases", () => {
  it("missing situationGraph → 400", async () => {
    const { POST } = await import("@/app/api/cases/synthesis/route.js");
    const res = await POST(makeRequest({ findings: [] }));

    expect(res.status).toBe(400);
    const data = await res.json();
    expect(data.success).toBe(false);
    expect(data.stage).toBe("request_validation");
  });

  it("invalid JSON body → 400", async () => {
    const req = new Request("http://localhost/api/cases/synthesis", {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: "not json",
    });
    const { POST } = await import("@/app/api/cases/synthesis/route.js");
    const res = await POST(req);

    expect(res.status).toBe(400);
  });

  it("null body → 400", async () => {
    const { POST } = await import("@/app/api/cases/synthesis/route.js");
    const res = await POST(makeRequest(null));

    expect(res.status).toBe(400);
  });

  it("domain seam throws with statusCode → mapped status", async () => {
    mockSynthesize.mockRejectedValue(new Error("Provider failed"));
    // Add statusCode property to the error object after creation
    const err = Object.assign(new Error("Provider failed"), { statusCode: 502 });
    mockSynthesize.mockRejectedValue(err);

    const { POST } = await import("@/app/api/cases/synthesis/route.js");
    const res = await POST(makeRequest({ situationGraph: makeValidGraph() }));

    expect(res.status).toBe(502);
    const data = await res.json();
    expect(data.success).toBe(false);
    expect(data.stage).toBe("provider");
  });

  it("domain seam throws without statusCode → 500", async () => {
    mockSynthesize.mockRejectedValue(new Error("unknown error"));

    const { POST } = await import("@/app/api/cases/synthesis/route.js");
    const res = await POST(makeRequest({ situationGraph: makeValidGraph() }));

    expect(res.status).toBe(500);
    const data = await res.json();
    expect(data.success).toBe(false);
    expect(data.stage).toBe("internal");
  });

  it("domain seam throws 400 → mapped to 400", async () => {
    const err = Object.assign(new Error("Invalid input"), { statusCode: 400 });
    mockSynthesize.mockRejectedValue(err);

    const { POST } = await import("@/app/api/cases/synthesis/route.js");
    const res = await POST(makeRequest({ situationGraph: makeValidGraph() }));

    expect(res.status).toBe(400);
    const data = await res.json();
    expect(data.success).toBe(false);
    expect(data.stage).toBe("request_validation");
  });
});

// ── Route thinness — no business logic in route ─────────────

describe("Route thinness", () => {
  beforeEach(() => mockSynthesize.mockClear());

  it("route does not filter eligibility itself (domain seam owns it)", async () => {
    mockSynthesize.mockResolvedValue({ currentUnderstanding: "OK" });
    const findings = [
      { id: "f1", proposition: "ineligible", userDisposition: "not_quite", evaluation: "considered" },
    ];

    const { POST } = await import("@/app/api/cases/synthesis/route.js");
    await POST(makeRequest({ situationGraph: makeValidGraph(), findings }));

    // Route passes all findings through — domain seam filters
    expect(mockSynthesize.mock.calls[0][0].findings).toHaveLength(1);
  });

  it("route does not construct prompts", async () => {
    mockSynthesize.mockResolvedValue({ currentUnderstanding: "OK" });

    const { POST } = await import("@/app/api/cases/synthesis/route.js");
    await POST(makeRequest({ situationGraph: makeValidGraph() }));

    expect(mockSynthesize).toHaveBeenCalledTimes(1);
  });

  it("route does not contain provider logic (delegates to domain seam)", async () => {
    mockSynthesize.mockResolvedValue({ currentUnderstanding: "OK" });

    const { POST } = await import("@/app/api/cases/synthesis/route.js");
    await POST(makeRequest({ situationGraph: makeValidGraph() }));

    expect(mockSynthesize).toHaveBeenCalledTimes(1);
  });
});