import { describe, test, expect, vi, beforeEach, afterEach } from "vitest";
import { PrologInterface } from "../../src/PrologInterface.js";
import { logger } from "../../src/logger.js";
describe("Session state behavior", () => {
const prevTrace = process.env.SWI_MCP_TRACE;
let warnSpy: ReturnType<typeof vi.spyOn>;
beforeEach(() => {
process.env.SWI_MCP_TRACE = "1";
warnSpy = vi.spyOn(logger, "warn").mockImplementation(() => {});
});
afterEach(() => {
warnSpy.mockRestore();
if (prevTrace === undefined) delete process.env.SWI_MCP_TRACE; else process.env.SWI_MCP_TRACE = prevTrace;
});
test("invalid transition logs a warning", () => {
const iface = new PrologInterface();
// idle -> query_completed is invalid; should log a warning
(iface as any).setSessionState("query_completed");
expect(warnSpy).toHaveBeenCalled();
});
test("query_completed yields no more solutions without process", async () => {
const iface = new PrologInterface();
// Simulate completed query state without an active process
(iface as any).queryActive = false;
(iface as any).sessionState = "query_completed";
const res = await iface.nextSolution();
expect(res.status).toBe("done");
expect(res.error).toBeUndefined();
});
test("engine_completed yields no more solutions without process", async () => {
const iface = new PrologInterface();
// Simulate completed engine state without an active process
(iface as any).engineActive = false;
(iface as any).engineReachedEOF = true;
(iface as any).sessionState = "engine_completed";
const res = await iface.nextEngine();
expect(res.status).toBe("done");
expect(res.error).toBeUndefined();
});
});
