diff --git a/src/core.cpp b/src/core.cpp
index 57b1a7f..ecb019a 100644
--- a/src/core.cpp
+++ b/src/core.cpp
@@ -262,7 +262,7 @@ inline std::ostream& repr(std::ostream& os, const HepMC3::GenEvent& x) {
 
 inline int gencrosssection_validate_index(GenCrossSection& cs, py::object obj) {
   auto idx = py::cast<int>(obj);
-  const auto size = cs.event() ? std::max(cs.event()->weights().size(), 1ul) : 1ul;
+  const auto size = cs.event() ? (std::max)(cs.event()->weights().size(), 1ul) : 1ul;
   if (idx < 0) idx += size;
   if (idx < 0 || idx >= size) throw py::index_error();
   return idx;
diff --git a/tests/test_basic.py b/tests/test_basic.py
index edb4c6c..281dc8c 100644
--- a/tests/test_basic.py
+++ b/tests/test_basic.py
@@ -140,7 +140,7 @@ def test_GenCrossSection():
         cs.xsec_err("baz")
 
 
-def test_attributes_0():
+def test_attributes_1():
     ri = hep.GenRunInfo()
     att = ri.attributes
     assert att == {}
@@ -177,10 +177,6 @@ def test_attributes_0():
     assert len(att) == 0
 
 
-def test_attributes_1():
-    pass
-
-
 def test_attributes_2(evt):
     att = evt.attributes
     assert att == {}