diff --git a/tests/test-math.c b/tests/test-math.c
index 2e2b3f191f..702c847992 100644
--- a/tests/test-math.c
+++ b/tests/test-math.c
@@ -191,6 +191,14 @@ int main(int argc, char** argv)
       }",
       NULL);
 
+  assert_true_rule(
+      "import \"math\" \
+      rule test { \
+        condition: \
+          math.entropy(\"\") == 0.0 \
+      }",
+      NULL);
+
   assert_true_rule(
       "import \"math\" \
       rule test { \