bendns' repos / rust-analyzer
Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'lib/smol_str/tests/test.rs')
-rw-r--r--lib/smol_str/tests/test.rs36
1 files changed, 36 insertions, 0 deletions
diff --git a/lib/smol_str/tests/test.rs b/lib/smol_str/tests/test.rs
index 537df8ddb2..934cfa3c05 100644
--- a/lib/smol_str/tests/test.rs
+++ b/lib/smol_str/tests/test.rs
@@ -215,4 +215,40 @@ fn test_from_char_iterator() {
assert_eq!(s.as_str(), *raw);
assert_eq!(s.is_heap_allocated(), *is_heap);
}
+ // String which has too many characters to even consider inlining: Chars::size_hint uses
+ // (`len` + 3) / 4. With `len` = 89, this results in 23, so `from_iter` will immediately
+ // heap allocate
+ let raw: String = std::iter::repeat('a').take(22 * 4 + 1).collect();
+ let s: SmolStr = raw.chars().collect();
+ assert_eq!(s.as_str(), raw);
+ assert!(s.is_heap_allocated());
+}
+
+#[test]
+fn test_bad_size_hint_char_iter() {
+ struct BadSizeHint<I>(I);
+
+ impl<T, I: Iterator<Item = T>> Iterator for BadSizeHint<I> {
+ type Item = T;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ self.0.next()
+ }
+
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ (1024, None)
+ }
+ }
+
+ let data = "testing";
+ let collected: SmolStr = BadSizeHint(data.chars()).collect();
+ let new = SmolStr::new(data);
+
+ // Because of the bad size hint, `collected` will be heap allocated, but `new` will be inline
+
+ // If we try to use the type of the string (inline/heap) to quickly test for equality, we need to ensure
+ // `collected` is inline allocated instead
+ assert!(collected.is_heap_allocated());
+ assert!(!new.is_heap_allocated());
+ assert_eq!(new, collected);
}