diff --git a/lib/cpp/test/Makefile.am b/lib/cpp/test/Makefile.am
index 5f3b117..162dc19 100755
--- a/lib/cpp/test/Makefile.am
+++ b/lib/cpp/test/Makefile.am
@@ -101,7 +101,7 @@
 TESTS_ENVIRONMENT= \
 	BOOST_TEST_LOG_SINK=tests.xml \
 	BOOST_TEST_LOG_LEVEL=test_suite \
-	BOOST_TEST_LOG_FORMAT=xml
+	BOOST_TEST_LOG_FORMAT=XML
 
 TESTS = \
 	$(check_PROGRAMS)