diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 1d1d10c8a..8e185944b 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -13,6 +13,8 @@ jobs:
         # We must fetch at least the immediate parents so that if this is
         # a pull request then we can checkout the head.
         fetch-depth: 2
+        # Fetch submodules
+        submodules: recursive
 
     # If this run was triggered by a pull request event, then checkout
     # the head of the pull request instead of the merge commit.