zcoord: add an overflow test

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/zcoord/zcoord.rs b/zcoord/zcoord.rs
index 12b926a2342323383c3d74ebd578e7252344cdf4..301782e3f0d586ab1ac125c0fcb50924ac30c60b 100644 (file)
--- a/zcoord/zcoord.rs
+++ b/zcoord/zcoord.rs
@@ -789,6 +789,7 @@ mod test {
       assert_eq!( &format!("{:?}", &l), &dbg );
     }
     chk(0x42, "0000000022");
+    chk(0x42 + RAW_LIMB_MODULUS * 0x33, "0x33!0000000022");
   }
 
   #[test]