diff --git a/.gitmodules b/.gitmodules
index 59fc63d..ad3e563 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -19,3 +19,6 @@
 [submodule "tests/_support_data/test-repo-submodules-multilevel"]
 	path = tests/_support_data/test-repo-submodules-multilevel
 	url = https://git.sw3.cz/kamikaze/test-repo-submodules-multilevel.git
+[submodule "tests/_support_data/test-repo-submodules-long"]
+	path = tests/_support_data/test-repo-submodules-long
+	url = https://git.sw3.cz/kamikaze/test-repo-submodules-long.git
diff --git a/tests/_support_data/test-repo-submodules-long b/tests/_support_data/test-repo-submodules-long
new file mode 160000
index 0000000..85cd87a
--- /dev/null
+++ b/tests/_support_data/test-repo-submodules-long
@@ -0,0 +1 @@
+Subproject commit 85cd87a2fefc9852215d7f6ea021c0fb4287b374