Working on a CLI tool for Noir development that works with Nargo projects. Some of my tests create Nargo projects (e.i. `nargo new test`), move some files in them and create new ones, so I can test stuff. I'm getting race conditions because the tests are run in parallel. Is there an easy solution like "use this crate"?

Tricks with polynomials and Riemann-Roch spaces. Breaking into the platonic realm to pillage forbidden abstractions. Starknet grantee.

planting causal loops; harvesting reflexivity

Yeah, I'm using tempfile but still getting some weird errors. Easiest one I can address right now goes like this:

Yes. The most straightforward solution is to isolate test environments using a crate that handles temporary directories safely and uniquely per test.

✅ Recommended Crate: tempfile

tempfile creates temporary directories/files that are guaranteed to be unique and automatically cleaned up. It solves your race condition problem by ensuring each test runs in its own isolated nargo project directory.

⸻

🧪 Usage Pattern

use tempfile::TempDir;
use std::process::Command;
use std::fs;

#[test]
fn test_nargo_project_setup() {
    let temp_dir = TempDir::new().unwrap();
    let project_path = temp_dir.path();

    // create a new Nargo project inside the temp dir
    let status = Command::new("nargo")
        .arg("new")
        .arg("test_project")
        .current_dir(&project_path)
        .status()
        .expect("failed to run nargo new");

    assert!(status.success());

    let test_proj_dir = project_path.join("test_project");

    // now you can move files or modify them safely in this isolated dir
    fs::write(test_proj_dir.join("src/main.nr"), "fn main() {}").unwrap();
}

Each test uses a fresh unique directory under /tmp (or OS equivalent). Running them in parallel no longer causes collisions.

⸻

🧩 Alternative: assert_fs

If you want test assertion helpers + file creation API, use assert_fs. It’s higher-level and often more ergonomic for file-system test scaffolding:

use assert_fs::prelude::*;
use std::process::Command;

#[test]
fn test_nargo_in_fs() {
    let temp = assert_fs::TempDir::new().unwrap();
    let status = Command::new("nargo")
        .arg("new")
        .arg("test_proj")
        .current_dir(&temp)
        .status()
        .unwrap();

    assert!(status.success());
    temp.child("test_proj").child("Nargo.toml").assert(predicates::path::exists());
}

⸻

🧷 Summary

Crate	Purpose	Use case
tempfile	Low-level unique temp file/dir	General isolation, raw control over file layout
assert_fs	High-level FS testing API + isolation	Tests that assert file presence, contents, structure

Both are well-suited for your situation. Pick based on ergonomics. assert_fs also integrates well with predicates.

Let me know if you want a macro-based helper or wrapper layer for test project creation.

chatgpt says temple or assert_fs https://chatgpt.com/share/68643b12-6f3c-800c-b071-dc9e1cc61a7b