1 files changed, 36 insertions, 0 deletions
diff --git a/third_party/rust/bitflags/src/tests/bits.rs b/third_party/rust/bitflags/src/tests/bits.rs
new file mode 100644
index 0000000000..678f153e36
--- /dev/null
+++ b/third_party/rust/bitflags/src/tests/bits.rs
@@ -0,0 +1,36 @@
+use super::*;
+
+use crate::Flags;
+
+#[test]
+fn cases() {
+    case(0, TestFlags::empty(), TestFlags::bits);
+
+    case(1, TestFlags::A, TestFlags::bits);
+    case(1 | 1 << 1 | 1 << 2, TestFlags::ABC, TestFlags::bits);
+
+    case(!0, TestFlags::from_bits_retain(u8::MAX), TestFlags::bits);
+    case(1 << 3, TestFlags::from_bits_retain(1 << 3), TestFlags::bits);
+
+    case(1 << 3, TestZero::from_bits_retain(1 << 3), TestZero::bits);
+
+    case(1 << 3, TestEmpty::from_bits_retain(1 << 3), TestEmpty::bits);
+
+    case(
+        1 << 4 | 1 << 6,
+        TestExternal::from_bits_retain(1 << 4 | 1 << 6),
+        TestExternal::bits,
+    );
+}
+
+#[track_caller]
+fn case<T: Flags + std::fmt::Debug>(
+    expected: T::Bits,
+    value: T,
+    inherent: impl FnOnce(&T) -> T::Bits,
+) where
+    T::Bits: std::fmt::Debug + PartialEq,
+{
+    assert_eq!(expected, inherent(&value), "{:?}.bits()", value);
+    assert_eq!(expected, Flags::bits(&value), "Flags::bits({:?})", value);
+}