diff --git a/.gitmodules b/.gitmodules
index 805e8a7..03410c2 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -19,3 +19,6 @@
 [submodule "Externals/lalr"]
 	path = Externals/lalr
 	url = https://github.com/IlyaShurupov/lalr.git
+[submodule "Externals/unittest-cpp"]
+	path = Externals/unittest-cpp
+	url = https://github.com/unittest-cpp/unittest-cpp.git
diff --git a/Externals/unittest-cpp b/Externals/unittest-cpp
new file mode 160000
index 0000000..10e50ad
--- /dev/null
+++ b/Externals/unittest-cpp
@@ -0,0 +1 @@
+Subproject commit 10e50ad70c696002b1d5bbefd0ea04b3ea92a03b