3 files changed, 17 insertions, 0 deletions
diff --git a/library/core/tests/ffi.rs b/library/core/tests/ffi.rs
new file mode 100644
index 00000000000..2b33fbd95f0
--- /dev/null
+++ b/library/core/tests/ffi.rs
@@ -0,0 +1 @@
+mod cstr;
diff --git a/library/core/tests/ffi/cstr.rs b/library/core/tests/ffi/cstr.rs
new file mode 100644
index 00000000000..9bf4c21a9ab
--- /dev/null
+++ b/library/core/tests/ffi/cstr.rs
@@ -0,0 +1,15 @@
+use core::ffi::CStr;
+
+#[test]
+fn compares_as_u8s() {
+    let a: &CStr = c"Hello!"; // Starts with ascii
+    let a_bytes: &[u8] = a.to_bytes();
+    assert!((..0b1000_0000).contains(&a_bytes[0]));
+
+    let b: &CStr = c"こんにちは！"; // Starts with non ascii
+    let b_bytes: &[u8] = b.to_bytes();
+    assert!((0b1000_0000..).contains(&b_bytes[0]));
+
+    assert_eq!(Ord::cmp(a, b), Ord::cmp(a_bytes, b_bytes));
+    assert_eq!(PartialOrd::partial_cmp(a, b), PartialOrd::partial_cmp(a_bytes, b_bytes));
+}
diff --git a/library/core/tests/lib.rs b/library/core/tests/lib.rs
index 83a615fcd8b..04aaa3f35b7 100644
--- a/library/core/tests/lib.rs
+++ b/library/core/tests/lib.rs
@@ -132,6 +132,7 @@ mod clone;
 mod cmp;
 mod const_ptr;
 mod convert;
+mod ffi;
 mod fmt;
 mod future;
 mod hash;