1 files changed, 42 insertions, 0 deletions
diff --git a/third_party/rust/bitflags/src/tests/extend.rs b/third_party/rust/bitflags/src/tests/extend.rs
new file mode 100644
index 0000000000..869dc17fc8
--- /dev/null
+++ b/third_party/rust/bitflags/src/tests/extend.rs
@@ -0,0 +1,42 @@
+use super::*;
+
+#[test]
+fn cases() {
+    let mut flags = TestFlags::empty();
+
+    flags.extend(TestFlags::A);
+
+    assert_eq!(TestFlags::A, flags);
+
+    flags.extend(TestFlags::A | TestFlags::B | TestFlags::C);
+
+    assert_eq!(TestFlags::ABC, flags);
+
+    flags.extend(TestFlags::from_bits_retain(1 << 5));
+
+    assert_eq!(TestFlags::ABC | TestFlags::from_bits_retain(1 << 5), flags);
+}
+
+mod external {
+    use super::*;
+
+    #[test]
+    fn cases() {
+        let mut flags = TestExternal::empty();
+
+        flags.extend(TestExternal::A);
+
+        assert_eq!(TestExternal::A, flags);
+
+        flags.extend(TestExternal::A | TestExternal::B | TestExternal::C);
+
+        assert_eq!(TestExternal::ABC, flags);
+
+        flags.extend(TestExternal::from_bits_retain(1 << 5));
+
+        assert_eq!(
+            TestExternal::ABC | TestExternal::from_bits_retain(1 << 5),
+            flags
+        );
+    }
+}