oh-my-pi/packages/tui/test/process-terminal-headless.test.ts

import { afterEach, beforeEach, describe, expect, it, vi } from "bun:test";
import { ProcessTerminal } from "@oh-my-pi/pi-tui/terminal";
import { isTerminalHeadless, setTerminalHeadless } from "@oh-my-pi/pi-utils";

// Regression: running `bun test` inside a real TTY used to paint the TUI frame,
// the start() capability probes (OSC 11 / DA1 / kitty), and the editor/status
// box straight to the developer's terminal — `#safeWrite` only skipped on
// `!process.stdout.isTTY`, which is false in an interactive terminal. The
// headless default (on under the test runtime) must suppress every real
// terminal side effect regardless of isTTY, while an explicit opt-out still
// drives the real pipeline for the terminal-contract suites.

const stdinIsTtyDescriptor = Object.getOwnPropertyDescriptor(process.stdin, "isTTY");
const stdoutIsTtyDescriptor = Object.getOwnPropertyDescriptor(process.stdout, "isTTY");
const stdinSetRawModeDescriptor = Object.getOwnPropertyDescriptor(process.stdin, "setRawMode");

function restoreProperty(target: object, key: string, descriptor: PropertyDescriptor | undefined): void {
	if (descriptor) {
		Object.defineProperty(target, key, descriptor);
		return;
	}
	delete (target as Record<string, unknown>)[key];
}

describe("ProcessTerminal headless suppression", () => {
	let writes: string[];
	let rawModeCalls: number;

	beforeEach(() => {
		writes = [];
		rawModeCalls = 0;
		// Force a real TTY: the exact condition under which the leak surfaced.
		Object.defineProperty(process.stdin, "isTTY", { value: true, configurable: true });
		Object.defineProperty(process.stdout, "isTTY", { value: true, configurable: true });
		Object.defineProperty(process.stdin, "setRawMode", {
			value: () => {
				rawModeCalls++;
				return process.stdin;
			},
			configurable: true,
		});
		vi.spyOn(process, "kill").mockReturnValue(true);
		vi.spyOn(process.stdin, "resume").mockImplementation(() => process.stdin);
		vi.spyOn(process.stdin, "pause").mockImplementation(() => process.stdin);
		vi.spyOn(process.stdin, "setEncoding").mockImplementation(() => process.stdin);
		vi.spyOn(process.stdout, "write").mockImplementation(chunk => {
			writes.push(typeof chunk === "string" ? chunk : chunk.toString());
			return true;
		});
	});

	afterEach(() => {
		vi.restoreAllMocks();
		restoreProperty(process.stdin, "isTTY", stdinIsTtyDescriptor);
		restoreProperty(process.stdout, "isTTY", stdoutIsTtyDescriptor);
		restoreProperty(process.stdin, "setRawMode", stdinSetRawModeDescriptor);
	});

	it("writes nothing to a real TTY while headless (the bun-test default)", () => {
		expect(isTerminalHeadless()).toBe(true);

		const terminal = new ProcessTerminal();
		// start() would emit OSC 11 + DA1 + kitty probes; write() a TUI frame;
		// setProgress() the OSC 9;4 keepalive; stop() the teardown escapes.
		terminal.start(
			() => {},
			() => {},
		);
		terminal.write("frame paint");
		terminal.setProgress(true);
		terminal.stop();

		expect(writes).toEqual([]);
		expect(rawModeCalls).toBe(0);
	});

	it("drives the real terminal once a suite opts out via setTerminalHeadless(false)", () => {
		const previous = setTerminalHeadless(false);
		const terminal = new ProcessTerminal();
		try {
			terminal.start(
				() => {},
				() => {},
			);
			terminal.write("frame paint");

			const emitted = writes.join("");
			expect(emitted).toContain("frame paint");
			// start() probes the background color (OSC 11) for dark/light detection.
			expect(emitted).toContain("\x1b]11;?");
		} finally {
			terminal.stop();
			setTerminalHeadless(previous);
		}
	});
});