fix test suite (pytest changes in ExceptionInfo class)
diff --git a/tests/test_local_bindings.py b/tests/test_local_bindings.py
index b3dc361..b380376 100644
--- a/tests/test_local_bindings.py
+++ b/tests/test_local_bindings.py
@@ -220,7 +220,7 @@
     c, d = m.MixGL2(3), cm.MixGL2(4)
     with pytest.raises(TypeError) as excinfo:
         m.get_gl_value(c)
-    assert "incompatible function arguments" in str(excinfo)
+    assert "incompatible function arguments" in str(excinfo.value)
     with pytest.raises(TypeError) as excinfo:
         m.get_gl_value(d)
-    assert "incompatible function arguments" in str(excinfo)
+    assert "incompatible function arguments" in str(excinfo.value)