Function spawn

packages/engine/src/utils/ffprobe.test.ts:134–163

(command: string, args: readonly string[])

  const calls: SpawnCall[] = [];
  let invocation = 0;
  const spawn = (command: string, args: readonly string[]): FakeProc => {
    calls.push({ command, args });
    const outcome = outcomes[invocation] ?? outcomes[outcomes.length - 1];
    invocation += 1;

    const proc = new EventEmitter() as FakeProc;
    proc.stdout = new EventEmitter();
    proc.stderr = new EventEmitter();

    process.nextTick(() => {
      if (!outcome) return;
      if (outcome.kind === "missing") {
        const err = new Error("spawn ffprobe ENOENT") as NodeJS.ErrnoException;
        err.code = "ENOENT";
        proc.emit("error", err);
        return;
      }
      if (outcome.kind === "error") {
        const err = new Error(outcome.message) as NodeJS.ErrnoException;
        if (outcome.code) err.code = outcome.code;
        proc.emit("error", err);
        return;
      }
      if (outcome.stdout) proc.stdout.emit("data", Buffer.from(outcome.stdout));
      if (outcome.stderr) proc.stderr.emit("data", Buffer.from(outcome.stderr));
      proc.emit("close", outcome.code);
    });

    return proc;
  };
  return { spawn, calls };
}