diff --git a/test/test-suite/test_foreign.py b/test/test-suite/test_foreign.py
index f07c8812..2f17cc2c 100644
--- a/test/test-suite/test_foreign.py
+++ b/test/test-suite/test_foreign.py
@@ -262,10 +262,12 @@ class TestForeign:
         q10 = im.jpegsave_buffer(Q=10)
         q10_subsample_off = im.jpegsave_buffer(Q=10, subsample_mode=2)
         q10_subsample_no = im.jpegsave_buffer(Q=10, no_subsample=1)
+        q10_subsample_no_and_subsample_mode_on = im.jpegsave_buffer(Q=10, no_subsample=1, subsample_mode=1)
         q90 = im.jpegsave_buffer(Q=90)
         assert len(q90) > len(q10)
         assert len(q10_subsample_off) > len(q10)
         assert len(q10_subsample_off) == len(q10_subsample_no)
+        assert len(q10_subsample_no_and_subsample_mode_on) == len(q10_subsample_no)
 
         # force subsampling should result in smaller buffer
         q90_subsample_on = im.jpegsave_buffer(Q=90, subsample_mode=1)