add CI test

Author: perazz

ci/run_tests.sh

@@ -344,5 +344,19 @@ pushd static_app_only
 test $EXIT_CODE -eq 0
 popd
 
+# Test custom module directory
+pushd custom_module_dir
+"$fpm" build
+rm -rf ./test_custom_install
+"$fpm" install --prefix ./test_custom_install
+# Verify modules are installed in custom directory
+test -f ./test_custom_install/custom/modules/greeting.mod
+test -f ./test_custom_install/custom/modules/math_utils.mod
+# Verify library is still installed normally
+test -f ./test_custom_install/lib/libcustom-module-dir.a
+# Clean up
+rm -rf ./test_custom_install
+popd
+
 # Cleanup
 rm -rf ./*/build