build: run testcases via autotools

Change-Id: Ie2aec28bac16388cef39558746dfe6ce8cba199e
Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
diff --git a/Makefile.am b/Makefile.am
index 07076d7..046ee20 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -14,3 +14,5 @@
 	sdbusplus/utility/tuple_to_array.hpp \
 	sdbusplus/utility/type_traits.hpp \
 	sdbusplus/vtable.hpp
+
+SUBDIRS = test