import { describe, test, expect } from "vitest";
import { PrologInterface } from "../../src/PrologInterface.js";
describe("Command queue isolation", () => {
test("continues after a failed command and resolves the next", async () => {
const iface = new PrologInterface();
// Stub a minimal process with a stdin.write we can control
let writeCall = 0;
const proc: any = {
stdin: {
write: (_data: string) => {
writeCall++;
if (writeCall === 1) {
// Simulate EPIPE by rejecting the first pending query asynchronously
setTimeout(() => {
const entry = (iface as any).queryPromises.get("0");
entry?.reject(new Error("Prolog process connection lost (EPIPE)"));
}, 0);
}
// succeed on subsequent writes
return true;
}
}
};
(iface as any).process = proc;
// First command should reject due to simulated EPIPE
const first = iface.query("first_command");
await expect(first).rejects.toThrow(/EPIPE|connection lost|not available/i);
// Second command should still run and be resolvable via response routing
const secondPromise = iface.query("second_command");
// Wait a tick to allow registration of the pending promise for id=1
await new Promise((r) => setTimeout(r, 0));
// Resolve the second by emitting a matching id response (id=1 after first failure)
(iface as any).processResponseLine("id(1, ok)");
await expect(secondPromise).resolves.toBe("ok");
});
});
