From 8a940481b003f64c9915b0292cf1b14c797fc559 Mon Sep 17 00:00:00 2001
From: Anand Aiyer <anand@aiyer.com>
Date: Fri, 17 Jul 2026 20:35:41 +0530
Subject: [PATCH] fix(tests): isolate Codex home from user state

Signed-off-by: Anand Aiyer <anand@aiyer.com>
---
 tests/test_cli.c  | 22 +++++++++++++++++++++-
 tests/test_main.c | 20 +++++++++++++-------
 2 files changed, 34 insertions(+), 8 deletions(-)

diff --git a/tests/test_cli.c b/tests/test_cli.c
index bb8a94b6f..395625325 100644
--- a/tests/test_cli.c
+++ b/tests/test_cli.c
@@ -226,6 +226,19 @@ static void restore_test_env(const char *name, char *saved) {
     }
 }
 
+TEST(cli_runner_uses_private_codex_home) {
+    const char *home = getenv("HOME");
+    const char *codex_home = getenv("CODEX_HOME");
+    ASSERT_NOT_NULL(home);
+    ASSERT_NOT_NULL(codex_home);
+
+    char expected[1024];
+    int expected_len = snprintf(expected, sizeof(expected), "%s/.codex", home);
+    ASSERT(expected_len >= 0 && (size_t)expected_len < sizeof(expected));
+    ASSERT_STR_EQ(codex_home, expected);
+    PASS();
+}
+
 /* Helper: mkdirp */
 static int test_mkdirp(const char *path) {
     char tmp[1024];
@@ -2354,10 +2367,13 @@ TEST(cli_detect_agents_finds_codex) {
     snprintf(dir, sizeof(dir), "%s/.codex", tmpdir);
     test_mkdirp(dir);
 
+    char *saved_codex = save_test_env("CODEX_HOME");
+    cbm_unsetenv("CODEX_HOME");
     cbm_detected_agents_t agents = cbm_detect_agents(tmpdir);
-    ASSERT_TRUE(agents.codex);
+    restore_test_env("CODEX_HOME", saved_codex);
 
     test_rmdir_r(tmpdir);
+    ASSERT_TRUE(agents.codex);
     PASS();
 }
 
@@ -2395,7 +2411,10 @@ TEST(cli_install_plan_receipt_no_mutation_issue388) {
     snprintf(dir, sizeof(dir), "%s/.codex", tmpdir);
     test_mkdirp(dir);
 
+    char *saved_codex = save_test_env("CODEX_HOME");
+    cbm_unsetenv("CODEX_HOME");
     char *json = cbm_build_install_plan_json(tmpdir, "/usr/local/bin/codebase-memory-mcp");
+    restore_test_env("CODEX_HOME", saved_codex);
     ASSERT_NOT_NULL(json);
     ASSERT(strstr(json, "agent.install.plan.v1") != NULL);
     ASSERT(strstr(json, "writes_started") != NULL);
@@ -9643,6 +9662,7 @@ TEST(cli_sha256_file_matches_known_vector) {
  * ═══════════════════════════════════════════════════════════════════ */
 
 SUITE(cli) {
+    RUN_TEST(cli_runner_uses_private_codex_home);
     RUN_TEST(cli_sha256_file_matches_known_vector);
     /* Version (2 tests — selfupdate_test.go) */
     RUN_TEST(cli_compare_versions);
diff --git a/tests/test_main.c b/tests/test_main.c
index ffbb1fb5c..18cc70a9c 100644
--- a/tests/test_main.c
+++ b/tests/test_main.c
@@ -25,10 +25,10 @@ int tf_skip_count = 0;
 #include <winsock2.h> /* #798 follow-up: socket-isolation re-exec probe */
 #endif
 
-/* Test handlers that exercise the production index_repository flow must never
- * inherit the user's real cache. Individual tests may temporarily override
- * this sentinel and restore it; atexit removes anything left behind by an
- * assertion that returns before fixture cleanup. */
+/* Test handlers that exercise production indexing or agent installation must
+ * never inherit the user's real cache or Codex configuration. Individual tests
+ * may temporarily override this sentinel and restore it; atexit removes
+ * anything left behind by an assertion that returns before fixture cleanup. */
 static char tf_home_sentinel[512];
 
 static void tf_cleanup_cache_sentinel(void) {
@@ -45,8 +45,14 @@ static bool tf_setup_cache_sentinel(void) {
     /* Legacy integration fixtures derive DB paths from HOME, while production
      * cache_dir() prefers CBM_CACHE_DIR. A private HOME plus no inherited cache
      * override keeps both conventions pointed at the same isolated tree. */
-    cbm_setenv("HOME", tf_home_sentinel, 1);
-    cbm_unsetenv("CBM_CACHE_DIR");
+    char codex_home[sizeof(tf_home_sentinel) + sizeof("/.codex")];
+    int codex_home_len = snprintf(codex_home, sizeof(codex_home), "%s/.codex", tf_home_sentinel);
+    if (codex_home_len < 0 || (size_t)codex_home_len >= sizeof(codex_home) ||
+        cbm_setenv("HOME", tf_home_sentinel, 1) != 0 ||
+        cbm_setenv("CODEX_HOME", codex_home, 1) != 0 || cbm_unsetenv("CBM_CACHE_DIR") != 0) {
+        tf_cleanup_cache_sentinel();
+        return false;
+    }
     atexit(tf_cleanup_cache_sentinel);
     return true;
 }
@@ -304,7 +310,7 @@ int main(int argc, char **argv) {
      * A test that exercises the supervisor must explicitly re-enable it. */
     cbm_setenv("CBM_INDEX_SUPERVISOR", "0", 1);
     if (!tf_setup_cache_sentinel()) {
-        fprintf(stderr, "failed to create isolated test cache\n");
+        fprintf(stderr, "failed to create isolated test home\n");
         return 2;
     }