1 files changed, 97 insertions, 0 deletions
diff --git a/third_party/rust/atomic_refcell/tests/basic.rs b/third_party/rust/atomic_refcell/tests/basic.rs
new file mode 100644
index 0000000000..5d859bb268
--- /dev/null
+++ b/third_party/rust/atomic_refcell/tests/basic.rs
@@ -0,0 +1,97 @@
+extern crate atomic_refcell;
+
+use atomic_refcell::{AtomicRef, AtomicRefCell, AtomicRefMut};
+
+struct Foo {
+    u: u32,
+}
+
+struct Bar {
+    f: Foo,
+}
+
+impl Default for Bar {
+    fn default() -> Self {
+        Bar { f: Foo { u: 42 } }
+    }
+}
+
+// FIXME(bholley): Add tests to exercise this in concurrent scenarios.
+
+#[test]
+fn immutable() {
+    let a = AtomicRefCell::new(Bar::default());
+    let _first = a.borrow();
+    let _second = a.borrow();
+}
+
+#[test]
+fn mutable() {
+    let a = AtomicRefCell::new(Bar::default());
+    let _ = a.borrow_mut();
+}
+
+#[test]
+fn interleaved() {
+    let a = AtomicRefCell::new(Bar::default());
+    {
+        let _ = a.borrow_mut();
+    }
+    {
+        let _first = a.borrow();
+        let _second = a.borrow();
+    }
+    {
+        let _ = a.borrow_mut();
+    }
+}
+
+#[test]
+#[should_panic(expected = "already immutably borrowed")]
+fn immutable_then_mutable() {
+    let a = AtomicRefCell::new(Bar::default());
+    let _first = a.borrow();
+    let _second = a.borrow_mut();
+}
+
+#[test]
+#[should_panic(expected = "already mutably borrowed")]
+fn mutable_then_immutable() {
+    let a = AtomicRefCell::new(Bar::default());
+    let _first = a.borrow_mut();
+    let _second = a.borrow();
+}
+
+#[test]
+#[should_panic(expected = "already mutably borrowed")]
+fn double_mutable() {
+    let a = AtomicRefCell::new(Bar::default());
+    let _first = a.borrow_mut();
+    let _second = a.borrow_mut();
+}
+
+#[test]
+fn map() {
+    let a = AtomicRefCell::new(Bar::default());
+    let b = a.borrow();
+    assert_eq!(b.f.u, 42);
+    let c = AtomicRef::map(b, |x| &x.f);
+    assert_eq!(c.u, 42);
+    let d = AtomicRef::map(c, |x| &x.u);
+    assert_eq!(*d, 42);
+}
+
+#[test]
+fn map_mut() {
+    let a = AtomicRefCell::new(Bar::default());
+    let mut b = a.borrow_mut();
+    assert_eq!(b.f.u, 42);
+    b.f.u = 43;
+    let mut c = AtomicRefMut::map(b, |x| &mut x.f);
+    assert_eq!(c.u, 43);
+    c.u = 44;
+    let mut d = AtomicRefMut::map(c, |x| &mut x.u);
+    assert_eq!(*d, 44);
+    *d = 45;
+    assert_eq!(*d, 45);
+}