diff --git a/tests/pam/Makefile.am b/tests/pam/Makefile.am
index 77b53de..3bf9597 100644
--- a/tests/pam/Makefile.am
+++ b/tests/pam/Makefile.am
@@ -1,6 +1,6 @@
 SUBDIRS = services
 
-TESTS_ENVIRONMENT = export TOPBUILDDIR=$(abs_top_builddir); export TOPSRCDIR=$(abs_top_srcdir); export LD_PRELOAD=libpam_wrapper.so; export PAM_WRAPPER_SERVICE_DIR=$(abs_top_builddir)/tests/pam/services; export PAM_WRAPPER=1; export PYTHON=@PYTHON@;
+TESTS_ENVIRONMENT = export TOPBUILDDIR=$(abs_top_builddir); export TOPSRCDIR=$(abs_top_srcdir); export LD_PRELOAD=libpam_wrapper.so; export PAM_WRAPPER_SERVICE_DIR=$(abs_top_builddir)/tests/pam/services; export PAM_WRAPPER=1; export PYTHON=@PYTHON@; export G_DEBUG=fatal_warnings;
 TESTS = test_pam_fprintd.py
 
 EXTRA_DIST = $(TESTS)