diff --git a/tests/conftest.py b/tests/conftest.py
index 5d0d79f4..5dabaf3e 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -46,6 +46,7 @@
       path: subdir/Kconfiglib
       groups:
         - Kconfiglib-group
+      submodules: true
     - name: tagged_repo
       revision: v1.0
     - name: net-tools
@@ -189,6 +190,7 @@ def repos_tmpdir(tmpdir, _session_repos):
         - name: Kconfiglib
           revision: zephyr
           path: subdir/Kconfiglib
+          submodules: true
         - name: tagged_repo
           revision: v1.0
         - name: net-tools
diff --git a/tests/test_project.py b/tests/test_project.py
index 9ba7b6ad..7fd88078 100644
--- a/tests/test_project.py
+++ b/tests/test_project.py
@@ -251,6 +251,7 @@ def test_manifest_freeze(west_update_tmpdir):
                     '^    path: subdir/Kconfiglib$',
                     '^    groups:$',
                     '^    - Kconfiglib-group$',
+                    '^    submodules: true$',
                     '^  - name: tagged_repo$',
                     '^    url: .*$',
                     '^    revision: [a-f0-9]{40}$',