diff --git a/test/error_code_test3.cpp b/test/error_code_test3.cpp
index 54d1468..6553c36 100644
--- a/test/error_code_test3.cpp
+++ b/test/error_code_test3.cpp
@@ -53,11 +53,17 @@ int main()
     BOOST_TEST_EQ( ec, en );
     BOOST_TEST_EQ( en, ec );
 
+    BOOST_TEST_EQ( ec, enomem_c );
+    BOOST_TEST_EQ( enomem_c, ec );
+
     BOOST_TEST_EQ( ec, enomem_n );
     BOOST_TEST_EQ( enomem_n, ec );
 
     BOOST_TEST_EQ( en, enomem_c );
     BOOST_TEST_EQ( enomem_c, en );
 
+    BOOST_TEST_EQ( en, enomem_n );
+    BOOST_TEST_EQ( enomem_n, en );
+
     return boost::report_errors();
 }