zcoord: Add a test for range carry/borrow edge case

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

diff --git a/base/zcoord.rs b/base/zcoord.rs
index dcb944dc249a013cb17f9d8954d4feddc55163ce..3c1168a7bc4a8b2a1cc4273d74f7113a347c328b 100644 (file)
--- a/base/zcoord.rs
+++ b/base/zcoord.rs
@@ -955,6 +955,14 @@ mod test {
     it.nxt("3333333334_000000000o");
     assert_eq!(it.i.next(), None);
 
+    let x = bf("aaaaaaaaaa_vvvvvvvvvv").clone_mut();
+    let y = bf("aaaaaaaaab"           ).clone_mut();
+    let i = x.range_upto(&y, 2).unwrap();
+    let mut it = It { i, last: x.repack().unwrap() };
+    it.nxt("aaaaaaaaaa_vvvvvvvvvv_alalalalal");
+    it.nxt("aaaaaaaaaa_vvvvvvvvvv_lalalalala");
+    assert_eq!(it.i.next(), None);
+
     let x = bf("1000000000").clone_mut();
     let y = bf("2000000000").clone_mut();
     let i = x.range_upto(&y, 3).unwrap();