tests: every test dir is removed when its test ends, pass or panic

Many test helpers removed their temp dir only before the test, or only
on pass, so runs left them behind: 117,000 filled /tmp (RAM here) and
stopped a mutation run. Each now holds a guard that removes the dir on
drop, unwind included; servers started on a test dir hold its guard
until they stop. A full cargo test --workspace leaves 0 dirs (859
before). just sweep-test-tmp stays for runs killed mid-test.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T3gXMVt7XJPi6ens1or9Dj

crates/ledger-store/tests/bounds.rs

@@ -21,14 +21,36 @@ use rust_decimal::Decimal;
 use serde_json::json;
 use std::path::PathBuf;
 
-fn test_dir(name: &str) -> PathBuf {
+/// A test's dir, removed when the test ends, pass or panic.
+struct TestDir(PathBuf);
+
+impl std::ops::Deref for TestDir {
+    type Target = std::path::Path;
+    fn deref(&self) -> &std::path::Path {
+        &self.0
+    }
+}
+
+impl AsRef<std::path::Path> for TestDir {
+    fn as_ref(&self) -> &std::path::Path {
+        &self.0
+    }
+}
+
+impl Drop for TestDir {
+    fn drop(&mut self) {
+        let _ = std::fs::remove_dir_all(&self.0);
+    }
+}
+
+fn test_dir(name: &str) -> TestDir {
     let dir = std::env::temp_dir().join(format!(
         "wanderbooks-store-bounds-{name}-{}",
         std::process::id()
     ));
     let _ = std::fs::remove_dir_all(&dir);
     std::fs::create_dir_all(&dir).unwrap();
-    dir
+    TestDir(dir)
 }
 
 fn d(y: i32, m: u32, day: u32) -> NaiveDate {
@@ -36,8 +58,8 @@ fn d(y: i32, m: u32, day: u32) -> NaiveDate {
 }
 
 /// The old-books fixture `name` (tests/fixtures/old-books: written by main
-/// 188c90ea), opened from a copy.
-fn open_old_books(name: &str) -> Store {
+/// 188c90ea), opened from a copy (kept while the guard lives).
+fn open_old_books(name: &str) -> (TestDir, Store) {
     let from = std::path::Path::new(env!("CARGO_MANIFEST_DIR"))
         .join("tests/fixtures/old-books")
         .join(name);
@@ -55,7 +77,8 @@ fn open_old_books(name: &str) -> Store {
             std::fs::copy(&e, to).unwrap();
         }
     }
-    Store::open(&dir).unwrap_or_else(|e| panic!("{name}: {e}"))
+    let store = Store::open(&dir).unwrap_or_else(|e| panic!("{name}: {e}"));
+    (dir, store)
 }
 
 /// Every file under `dir`.
@@ -114,7 +137,7 @@ fn a_statement_the_books_cant_hold_is_refused() {
         .unwrap();
     // A statement an earlier version recorded past both bounds opens, its
     // balances as recorded.
-    let old = open_old_books("x_statement_max");
+    let (_dir, old) = open_old_books("x_statement_max");
     let recorded = old.statements(None).unwrap();
     assert_eq!(
         recorded[0].closing_balance,
@@ -158,7 +181,7 @@ fn a_recurring_run_has_an_end() {
     assert!(s.run_recurring(last).unwrap().is_empty());
     // One run an earlier version made of more than that opens, every
     // draft as generated.
-    let old = open_old_books("x_recurring_run_1044");
+    let (_dir, old) = open_old_books("x_recurring_run_1044");
     assert_eq!(old.ledger().next_entry_id(), 1045);
     old.verify().unwrap();
 }
@@ -206,7 +229,7 @@ fn disposal_proceeds_larger_than_a_line_are_refused() {
         assert!(s.run_depreciation(id, period).is_err(), "{period}");
     }
     // Depreciation an earlier version posted for 10000-01 opens.
-    let old = open_old_books("x_depreciation_year10000");
+    let (_dir, old) = open_old_books("x_depreciation_year10000");
     assert_eq!(old.ledger().get_entry(2).unwrap().date(), d(10000, 1, 31));
 }