diff --git a/.gitmodules b/.gitmodules
index 995e15b..f3c2857 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -4,3 +4,6 @@
 [submodule "lib/variant"]
 	path = lib/variant
 	url = https://github.com/mapbox/variant
+[submodule "tests/data/pddl-instances"]
+	path = tests/data/pddl-instances
+	url = https://github.com/potassco/pddl-instances.git
diff --git a/lib/pddlparse/tests/main.cpp b/lib/pddlparse/tests/main.cpp
index e622792..6e97333 100644
--- a/lib/pddlparse/tests/main.cpp
+++ b/lib/pddlparse/tests/main.cpp
@@ -7,6 +7,7 @@
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
+// TODO: reimplement unit tests
 int main()
 {
 	const pddl::Context::WarningCallback ignoreWarnings = [](const auto &, const auto &){};
@@ -19,4 +20,8 @@ int main()
 	const auto description = pddl::parseDescription(context);
 
 	std::cout << description.domain->requirements.size() << std::endl;
+	std::cout << description.domain->predicates.size() << std::endl;
+	std::cout << description.domain->actions.size() << std::endl;
+	std::cout << description.problem.value()->name << std::endl;
+	std::cout << description.problem.value()->objects.size() << std::endl;
 }
diff --git a/tests/data/pddl-instances b/tests/data/pddl-instances
new file mode 160000
index 0000000..bf7062d
--- /dev/null
+++ b/tests/data/pddl-instances
@@ -0,0 +1 @@
+Subproject commit bf7062de90321c8a2e3f898f1a4c4e4b0b1d1515