add unit test to bootstrap:util:cache:tests

src/bootstrap/src/utils/cache.rs

@@ -298,3 +298,6 @@ impl Cache {
         self.0.borrow().contains_key(&TypeId::of::<S>())
     }
 }
+
+#[cfg(test)]
+mod tests;

src/bootstrap/src/utils/cache/tests.rs

@@ -0,0 +1,52 @@
+use std::path::PathBuf;
+
+use crate::utils::cache::{INTERNER, Internable, TyIntern};
+
+#[test]
+fn test_string_interning() {
+    let s1 = INTERNER.intern_str("Hello");
+    let s2 = INTERNER.intern_str("Hello");
+    let s3 = INTERNER.intern_str("world");
+
+    assert_eq!(s1, s2, "Same strings should be interned to the same instance");
+    assert_ne!(s1, s3, "Different strings should have different interned values");
+}
+
+#[test]
+fn test_path_interning() {
+    let p1 = PathBuf::from("/tmp/file").intern();
+    let p2 = PathBuf::from("/tmp/file").intern();
+    let p3 = PathBuf::from("/tmp/other").intern();
+
+    assert_eq!(p1, p2);
+    assert_ne!(p1, p3);
+}
+
+#[test]
+fn test_vec_interning() {
+    let v1 = vec!["a".to_string(), "b".to_string()].intern();
+    let v2 = vec!["a".to_string(), "b".to_string()].intern();
+    let v3 = vec!["c".to_string()].intern();
+
+    assert_eq!(v1, v2);
+    assert_ne!(v1, v3);
+}
+
+#[test]
+fn test_interned_equality() {
+    let s1 = INTERNER.intern_str("test");
+    let s2 = INTERNER.intern_str("test");
+
+    assert_eq!(s1, s2);
+    assert_eq!(s1, "test");
+}
+
+#[test]
+fn test_ty_intern_intern_borrow() {
+    let mut interner = TyIntern::default();
+    let s1 = interner.intern_borrow("borrowed");
+    let s2 = interner.intern("borrowed".to_string());
+
+    assert_eq!(s1, s2);
+    assert_eq!(interner.get(s1), "borrowed");
+}