import { describe, expect, it } from "vitest";
import {
  assertTransition,
  canTransition,
  IllegalTransition,
} from "@/services/state-machine";

describe("state-machine", () => {
  it("allows FETCHED → PARSING", () => {
    expect(canTransition("FETCHED", "PARSING")).toBe(true);
  });
  it("allows PARSING → PENDING_CONFIRM", () => {
    expect(() => assertTransition("PARSING", "PENDING_CONFIRM")).not.toThrow();
  });
  it("rejects SUCCESS → PARSING", () => {
    expect(() => assertTransition("SUCCESS", "PARSING")).toThrow(IllegalTransition);
  });
  it("allows PARSE_FAILED → PARSING", () => {
    expect(canTransition("PARSE_FAILED", "PARSING")).toBe(true);
  });
  it("allows PARSING → FETCHED (stale reaper)", () => {
    expect(canTransition("PARSING", "FETCHED")).toBe(true);
  });
});