tempfile: use new logic for uvar tests

The old approach does not properly protect from concurrent tests
accessing the same tempdir. Fix this by moving to the new tempfile
functionality. This also eliminates the need to explicitly create and
delete the directory. There is also no longer a reason to specify names
for the temporary directories, since name collisions are avoided using
more robust means, and there is little benefit to having the names in
the directory name.

Closes #12030

src/env_universal_common.rs

@@ -806,7 +806,10 @@ fn skip_spaces(mut s: &wstr) -> &wstr {
 
 #[cfg(test)]
 mod tests {
+    use fish_tempfile::TempDir;
+
     use crate::common::ENCODE_DIRECT_BASE;
+    use crate::common::bytes2wcstring;
     use crate::common::char_offset;
     use crate::common::wcs2osstring;
     use crate::env::{EnvVar, EnvVarFlags, VarTable};
@@ -817,16 +820,14 @@ mod tests {
 
     const UVARS_PER_THREAD: usize = 8;
 
-    /// Creates a unique temporary directory and file path for universal variable tests.
-    /// Returns (directory_path, file_path).
-    fn make_test_uvar_path(test_name: &str) -> (std::path::PathBuf, WString) {
-        let test_dir = std::env::temp_dir().join(format!(
-            "fish_test_{}_{:?}",
-            test_name,
-            std::thread::current().id()
-        ));
-        let test_path = sprintf!("%s/varsfile.txt", test_dir.to_string_lossy());
-        (test_dir, test_path)
+    /// Creates a unique temporary directory and file path for universal variable tests inside the
+    /// new tempdir.
+    /// Returns (temp_dir, file_path).
+    fn make_test_uvar_path() -> std::io::Result<(TempDir, WString)> {
+        let temp_dir = fish_tempfile::new_dir()?;
+        let file_path = temp_dir.path().join("varsfile.txt");
+        let file_path = bytes2wcstring(file_path.as_os_str().as_encoded_bytes());
+        Ok((temp_dir, file_path))
     }
 
     fn test_universal_helper(x: usize, path: &wstr) {
@@ -854,9 +855,7 @@ fn test_universal_helper(x: usize, path: &wstr) {
     #[test]
     fn test_universal() {
         let _cleanup = test_init();
-        let (test_dir, test_path) = make_test_uvar_path("universal");
-        let _ = std::fs::remove_dir_all(&test_dir);
-        std::fs::create_dir_all(&test_dir).unwrap();
+        let (_test_dir, test_path) = make_test_uvar_path().unwrap();
 
         let threads = 1;
         let mut handles = Vec::new();
@@ -890,8 +889,6 @@ fn test_universal() {
                 assert_eq!(var, expected_val);
             }
         }
-
-        std::fs::remove_dir_all(&test_dir).unwrap();
     }
 
     #[test]
@@ -1035,8 +1032,7 @@ fn test_universal_parsing_legacy() {
     #[test]
     fn test_universal_callbacks() {
         let _cleanup = test_init();
-        let (test_dir, test_path) = make_test_uvar_path("callbacks");
-        std::fs::create_dir_all(&test_dir).unwrap();
+        let (_test_dir, test_path) = make_test_uvar_path().unwrap();
         let mut uvars1 = EnvUniversal::new();
         let mut uvars2 = EnvUniversal::new();
         let mut callbacks = uvars1
@@ -1100,7 +1096,6 @@ macro_rules! sync {
         assert_eq!(callbacks[1].val.as_ref().unwrap().as_string(), L!("1"));
         assert_eq!(callbacks[2].key, L!("delta"));
         assert_eq!(callbacks[2].val, None);
-        std::fs::remove_dir_all(&test_dir).unwrap();
     }
 
     #[test]
@@ -1129,8 +1124,7 @@ macro_rules! validate {
     fn test_universal_ok_to_save() {
         let _cleanup = test_init();
         // Ensure we don't try to save after reading from a newer fish.
-        let (test_dir, test_path) = make_test_uvar_path("ok_to_save");
-        std::fs::create_dir_all(&test_dir).unwrap();
+        let (_test_dir, test_path) = make_test_uvar_path().unwrap();
         let contents = b"# VERSION: 99999.99\n";
         std::fs::write(wcs2osstring(&test_path), contents).unwrap();
 
@@ -1152,6 +1146,5 @@ fn test_universal_ok_to_save() {
         // Ensure file is same.
         let after_id = file_id_for_path(&test_path);
         assert_eq!(before_id, after_id, "test_path should not have changed",);
-        std::fs::remove_dir_all(&test_dir).unwrap();
     }
 }