From 05565ee8a2a54b340305cde25eb93c7fb69e21c5 Mon Sep 17 00:00:00 2001
From: claude <claude@mycelium.de>
Date: Mon, 13 Jul 2026 19:40:59 +0200
Subject: [PATCH] =?UTF-8?q?test:=20red=20for=20#258=20=E2=80=94=20temp=5Fc?=
 =?UTF-8?q?wd=20sandbox=20leaks=20one=20dir=20per=20run=20into=20/tmp?=
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The helper keys its sandbox on std::process::id() under env::temp_dir(),
so the pre-create wipe never matches a prior run's path: one directory
strands per test-binary invocation on the 16 GiB tmpfs (>50k dirs by
2026-07-13). The test pins the property at one representative site: the
returned path embeds no PID and lives off env::temp_dir().

refs #258
---
 crates/aura-cli/tests/project_nodes.rs | 33 ++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/crates/aura-cli/tests/project_nodes.rs b/crates/aura-cli/tests/project_nodes.rs
index cccba91..561bdd1 100644
--- a/crates/aura-cli/tests/project_nodes.rs
+++ b/crates/aura-cli/tests/project_nodes.rs
@@ -18,6 +18,39 @@ fn aura(args: &[&str], cwd: &Path) -> std::process::Output {
         .expect("spawn aura")
 }
 
+/// Property (#258): a test sandbox must not outlive its run — `temp_cwd` must
+/// hand back a run-STABLE path that lives off the `env::temp_dir()` tmpfs, so
+/// its own pre-create `remove_dir_all` reclaims the previous run instead of
+/// stranding one `aura-nodes-*` directory per test-binary invocation.
+///
+/// The helper today keys the name on `std::process::id()`, so every run mints a
+/// new path the wipe can never match: >50 000 leaked dirs filled a 16 GiB tmpfs
+/// to 100%. The in-repo remedy is the knob-lab scaffold's (commit 84e1075, sibling
+/// `project_sweep_campaign.rs`): a fixed name under `CARGO_TARGET_TMPDIR`. This
+/// pins that property at one representative site — the assertion reads the path
+/// value only, so it is deterministic and does not depend on any external state.
+#[test]
+fn temp_cwd_sandbox_does_not_leak_under_env_temp_dir() {
+    let sandbox = temp_cwd("leakguard");
+    // Read the path value, then reclaim immediately so a red run of this very
+    // test does not itself add to the leak it describes.
+    let path = sandbox.clone();
+    let _ = std::fs::remove_dir_all(&sandbox);
+
+    let pid = std::process::id().to_string();
+    assert!(
+        !path.to_string_lossy().contains(&pid),
+        "sandbox name embeds the pid ({pid}), so no later run's pre-create wipe \
+         can reclaim it — one directory leaks per run: {}",
+        path.display(),
+    );
+    assert!(
+        !path.starts_with(std::env::temp_dir()),
+        "sandbox lives under env::temp_dir() — the tmpfs the >50k-dir leak filled: {}",
+        path.display(),
+    );
+}
+
 #[test]
 fn nodes_new_scaffolds_a_sibling_crate_and_attaches_it() {
     let cwd = temp_cwd("attach");