From 543d3aba7980a265a6d9628c3506052c334dbb44 Mon Sep 17 00:00:00 2001
From: zackees <z@zackees.com>
Date: Fri, 24 Jul 2026 23:14:44 -0700
Subject: [PATCH] fix(test): serialize LPC environment override tests

---
 crates/fbuild-deploy/src/lpc.rs | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/crates/fbuild-deploy/src/lpc.rs b/crates/fbuild-deploy/src/lpc.rs
index 80abced89..161e26ef8 100644
--- a/crates/fbuild-deploy/src/lpc.rs
+++ b/crates/fbuild-deploy/src/lpc.rs
@@ -707,6 +707,12 @@ fn port_names_match(sys: &str, user: &str) -> bool {
 mod tests {
     use super::*;
 
+    // The resolver tests below temporarily mutate the same process-wide
+    // override. Cargo runs unit tests in parallel, so serialize that narrow
+    // shared state rather than letting one test restore the other test's
+    // value (which was visible as a Windows-only intermittent miss).
+    static LPC21ISP_ENV_LOCK: std::sync::Mutex<()> = std::sync::Mutex::new(());
+
     #[test]
     fn test_lpc_deployer_creation() {
         let deployer = LpcDeployer::new("115200", 12_000, 60, None, false);
@@ -830,6 +836,9 @@ mod tests {
 
     #[test]
     fn find_lpc21isp_env_var_wins_when_pointing_at_real_file() {
+        let _guard = LPC21ISP_ENV_LOCK
+            .lock()
+            .unwrap_or_else(|error| error.into_inner());
         let tmp = tempfile::TempDir::new().unwrap();
         let fake = tmp.path().join(if cfg!(windows) {
             "lpc21isp.exe"
@@ -854,6 +863,9 @@ mod tests {
 
     #[test]
     fn find_lpc21isp_env_var_missing_file_falls_through() {
+        let _guard = LPC21ISP_ENV_LOCK
+            .lock()
+            .unwrap_or_else(|error| error.into_inner());
         // Env var pointing at a non-existent path should be treated as
         // "not configured" rather than a hard error — the resolver
         // continues to the next search location.