diff --git a/tests/Makefile.am b/tests/Makefile.am
index 3d12fff7..a573a1c9 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -78,7 +78,7 @@ noinst_PROGRAMS =
 
 # Basic includes
 AM_CFLAGS = -g
-AM_CPPFLAGS = -I$(top_srcdir)/src -I$(top_srcdir)/src/transport_layer -I$(top_srcdir)/src/routing_layer -I$(top_srcdir)/lib
+AM_CPPFLAGS = -I$(top_srcdir)/src -I$(top_srcdir)/src/transport_layer -I$(top_srcdir)/src/routing_layer -I$(top_srcdir)/lib -I$(srcdir)
 LIBUTUN = $(top_builddir)/src/libutun.a
 
 # Windows-specific libraries