diff --git a/build-constraints.yaml b/build-constraints.yaml
index 142c8e26..cd7887d6 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -3839,6 +3839,9 @@ expected-test-failures:
     # https://github.com/kazu-yamamoto/word8/issues/5
     - word8
 
+    # https://github.com/pruvisto/heap/issues/4
+    - heap
+
 # end of expected-test-failures
 
 # Benchmarks which are known not to build. Note that, currently we do not run