fix(rust/driver_manager): try to fix flaky test (#4028)

For some reason the hierarchical path profile test is flaky, let's try
to fix that

Author: zeroshade

rust/Cargo.lock

@@ -57,5 +57,6 @@ windows-registry = { version = ">= 0.5.3" }
 
 [dev-dependencies]
 arrow-select.workspace = true
+serial_test = "3.4.0"
 temp-env = "0.3"
 tempfile = "3.26"

rust/driver_manager/Cargo.toml

@@ -869,27 +869,16 @@ pub(crate) fn find_filesystem_profile(
 
     // Search in the configured paths
     let path_list = get_profile_search_paths(additional_path_list);
-    let has_toml_ext = profile_path.extension().is_some_and(|ext| ext == "toml");
 
+    let actual_path = profile_path.with_extension("toml");
     path_list
         .iter()
         .find_map(|path| {
-            let mut full_path = path.join(profile_path.as_path());
-            if has_toml_ext {
-                // Name already has .toml extension, use it as-is
-                if full_path.is_file() {
-                    Some(full_path)
-                } else {
-                    None
-                }
+            let full_path = path.join(actual_path.as_path());
+            if full_path.is_file() {
+                Some(full_path)
             } else {
-                // try adding .toml extension
-                full_path.set_extension("toml");
-                if full_path.is_file() {
-                    Some(full_path)
-                } else {
-                    None
-                }
+                None
             }
         })
         .ok_or_else(|| {

rust/driver_manager/src/search.rs

@@ -23,6 +23,7 @@ use adbc_driver_manager::profile::{
     ConnectionProfile, ConnectionProfileProvider, FilesystemProfileProvider,
 };
 use adbc_driver_manager::ManagedDatabase;
+use serial_test::serial;
 
 mod common;
 
@@ -432,6 +433,7 @@ fn test_profile_display() {
 }
 
 #[test]
+#[serial]
 fn test_profile_hierarchical_path_via_env_var() {
     use std::env;
 
@@ -496,6 +498,7 @@ fn test_profile_hierarchical_path_via_env_var() {
 }
 
 #[test]
+#[serial]
 fn test_profile_hierarchical_path_with_extension_via_env_var() {
     use std::env;