// Nightly: requires a non-core registry command.import { existsSync } from "node:fs";import { mkdir, mkdtemp, rm, writeFile } from "node:fs/promises";import { tmpdir } from "node:os";import { dirname, join } from "node:path";import { fileURLToPath } from "node:url";import {	NodeFileSystem,	createKernel,	createWasmVmRuntime,	describeIf,} from "@rivet-dev/agentos-test-harness";import type { Kernel } from "@rivet-dev/agentos-test-harness";import { afterEach, expect, it } from "vitest"; const DIFF_COMMAND_DIR = fileURLToPath(new URL("../bin", import.meta.url));const hasDiffPackageBinary = existsSync(join(DIFF_COMMAND_DIR, "diff")); let tempRoot: string | undefined; async function writeFixture(path: string, contents: string): Promise<void> {	if (!tempRoot) throw new Error("fixture root not initialized");	const hostPath = join(tempRoot, path.replace(/^\/+/, ""));	await mkdir(dirname(hostPath), { recursive: true });	await writeFile(hostPath, contents);} async function createTestVFS(): Promise<NodeFileSystem> {	tempRoot = await mkdtemp(join(tmpdir(), "agentos-diff-"));	await writeFixture("/project/a.txt", "alpha\nbeta\ngamma\n");	await writeFixture("/project/b.txt", "alpha\ndelta\ngamma\n");	await writeFixture("/project/same.txt", "alpha\nbeta\ngamma\n");	await writeFixture("/project/ws-a.txt", "Alpha\n\nbeta value\n");	await writeFixture("/project/ws-b.txt", "alpha\n BETA   VALUE\n");	await writeFixture("/project/left/common.txt", "one\ntwo\nthree\n");	await writeFixture("/project/right/common.txt", "one\n2\nthree\n");	await writeFixture("/project/right/extra.txt", "only on right\n");	return new NodeFileSystem({ root: tempRoot });} describeIf(hasDiffPackageBinary, "diff command", { timeout: 10_000 }, () => {	let kernel: Kernel | undefined; 	afterEach(async () => {		await kernel?.dispose();		kernel = undefined;		if (tempRoot) {			await rm(tempRoot, { recursive: true, force: true });			tempRoot = undefined;		}	}); 	async function mountFixture(): Promise<void> {		const vfs = await createTestVFS();		kernel = createKernel({ filesystem: vfs });		await kernel.mount(createWasmVmRuntime({ commandDirs: [DIFF_COMMAND_DIR] }));	} 	async function runDiff(args: string[]) {		if (!kernel) throw new Error("kernel not mounted");		let stdout = "";		let stderr = "";		const proc = kernel.spawn("diff", args, {			onStdout: (chunk) => {				stdout += Buffer.from(chunk).toString("utf8");			},			onStderr: (chunk) => {				stderr += Buffer.from(chunk).toString("utf8");			},		});		const exitCode = await proc.wait();		await new Promise<void>((resolve) => setTimeout(resolve, 0));		return { stdout, stderr, exitCode };	} 	it("returns zero for identical files", async () => {		await mountFixture(); 		const result = await runDiff(["/project/a.txt", "/project/same.txt"]);		expect(result.exitCode, result.stderr || result.stdout).toBe(0);		expect(result.stdout).toBe("");	}); 	it("prints normal diffs for changed files", async () => {		await mountFixture(); 		const result = await runDiff(["/project/a.txt", "/project/b.txt"]);		expect(result.exitCode).toBe(1);		expect(result.stdout).toContain("2c2");		expect(result.stdout).toContain("< beta");		expect(result.stdout).toContain("> delta");	}); 	it("prints unified diffs", async () => {		await mountFixture(); 		const result = await runDiff(["-u", "/project/a.txt", "/project/b.txt"]);		expect(result.exitCode).toBe(1);		expect(result.stdout).toContain("--- /project/a.txt");		expect(result.stdout).toContain("+++ /project/b.txt");		expect(result.stdout).toContain("-beta");		expect(result.stdout).toContain("+delta");	}); 	it("prints brief output with -q", async () => {		await mountFixture(); 		const result = await runDiff(["-q", "/project/a.txt", "/project/b.txt"]);		expect(result.exitCode).toBe(1);		expect(result.stdout.trim()).toBe(			"Files /project/a.txt and /project/b.txt differ",		);	}); 	it("honors ignore-case, whitespace, and blank-line flags", async () => {		await mountFixture(); 		const result = await runDiff([			"-i",			"-w",			"-B",			"/project/ws-a.txt",			"/project/ws-b.txt",		]);		expect(result.exitCode, result.stderr || result.stdout).toBe(0);		expect(result.stdout).toBe("");	}); 	it("compares directories recursively", async () => {		await mountFixture(); 		const result = await runDiff(["-r", "/project/left", "/project/right"]);		expect(result.exitCode).toBe(1);		expect(result.stdout).toContain("Only in /project/right: extra.txt");		expect(result.stdout).toContain("/project/left/common.txt");		expect(result.stdout).toContain("/project/right/common.txt");	}); 	it("returns an error for missing inputs", async () => {		await mountFixture(); 		const result = await runDiff(["/project/a.txt", "/project/missing.txt"]);		expect(result.exitCode).toBe(2);		expect(result.stderr).toContain("/project/missing.txt");	});});