diff --git a/tests/meson.build b/tests/meson.build
index f2c0134f59c8c6b5513e872cc60d2ce0948b8533..c88ddd489d466c0bcbab989eab10c8965829903b 100644
--- a/tests/meson.build
+++ b/tests/meson.build
@@ -46,6 +46,7 @@ tests = {
 		  },
 		}
 
+undef_ndebug = '-UNDEBUG'
 test_env = environment(
   {
 	# Set glibc's MALLOC_PERTURB to 1. This means that newly allocated
@@ -71,6 +72,8 @@ foreach source, test_dict : tests
   test_exe = executable(test_name,
 						source,
 						include_directories: emper_all_include,
+						c_args: undef_ndebug,
+						cpp_args: undef_ndebug,
 						dependencies: emper_dependencies + test_dep,
 						link_with: [emper, emper_c],
 					   )