diff --git a/python/tests/test_haplotype_matching.py b/python/tests/test_haplotype_matching.py
index 0b00e8cb00..1bb3a27bf9 100644
--- a/python/tests/test_haplotype_matching.py
+++ b/python/tests/test_haplotype_matching.py
@@ -1179,7 +1179,7 @@ def check_backward_matrix(ts, h, forward_cm, recombination=None, mutation=None):
 
     B = ls.backwards(
         reference_panel=G,
-        query=h.reshape(1, m),
+        query=s,
         ploidy=1,
         normalisation_factor_from_forward=forward_cm.normalisation_factor,
         prob_recombination=recombination,