bun.sh/test/js/node/process/process-stdin.test.ts

import { expect, test } from "bun:test";
import { bunEnv, bunExe } from "harness";

test("pipe does the right thing", async () => {
  // Note: Bun.spawnSync uses memfd_create on Linux for pipe, which means we see
  // it as a file instead of a tty
  const result = Bun.spawn({
    cmd: [bunExe(), "-e", "console.log(typeof process.stdin.ref)"],
    stdin: "pipe",
    stdout: "pipe",
    stderr: "inherit",
    env: bunEnv,
  });

  expect((await new Response(result.stdout).text()).trim()).toBe("function");
  expect(await result.exited).toBe(0);
});

test("file does the right thing", async () => {
  const result = Bun.spawn({
    cmd: [bunExe(), "-e", "console.log(typeof process.stdin.ref)"],
    stdin: Bun.file(import.meta.path),
    stdout: "pipe",
    stderr: "inherit",
    env: bunEnv,
  });

  expect((await new Response(result.stdout).text()).trim()).toBe("undefined");
  expect(await result.exited).toBe(0);
});