rea/src/process/ExecFileOutput.test.ts

import { describe, expect, it } from "vitest";

import { execFileOutput } from "./ExecFileOutput.js";

describe("execFileOutput", () => {
  it("captures output larger than Node's default execFile limit", async () => {
    const marker = "tail-marker";
    const result = await execFileOutput(process.execPath, [
      "-e",
      `process.stdout.write("x".repeat(2 * 1024 * 1024)); process.stdout.write(${JSON.stringify(marker)});`,
    ]);

    expect(result.stdout).toHaveLength(2 * 1024 * 1024 + marker.length);
    expect(result.stdout.endsWith(marker)).toBe(true);
  });

  it("enforces a caller supplied output bound", async () => {
    await expect(
      execFileOutput(
        process.execPath,
        ["-e", 'process.stdout.write("x".repeat(1024))'],
        { maxBuffer: 64 },
      ),
    ).rejects.toMatchObject({ code: "ERR_CHILD_PROCESS_STDIO_MAXBUFFER" });
  });

  it("retains both captured streams on a failed child process", async () => {
    await expect(
      execFileOutput(process.execPath, [
        "-e",
        'process.stdout.write("out"); process.stderr.write("err"); process.exitCode = 7;',
      ]),
    ).rejects.toMatchObject({ code: 7, stdout: "out", stderr: "err" });
  });
});