test

Author: workingjubilee

library/std/src/sys_common/wtf8/tests.rs

@@ -725,3 +725,12 @@ fn wtf8_utf8_boundary_between_surrogates() {
     string.push(CodePoint::from_u32(0xD800).unwrap());
     check_utf8_boundary(&string, 3);
 }
+
+#[test]
+fn wtf8_not_utf8_isnt_utf8() {
+    let mut string: Wtf8Buf = unsafe { Wtf8::from_bytes_unchecked(b"\xED\xA0\x80").to_owned() };
+    assert_eq!(string.bytes, b"\xED\xA0\x80");
+    assert!(!string.is_known_utf8);
+    string.extend_from_slice(b"some utf-8");
+    assert!(!string.is_known_utf8);
+}