diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 12a81fb..89d8588 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -10,6 +10,8 @@ jobs:
         nim: [stable, 1.6.16, 1.4.8, 1.2.18]
     steps:
     - uses: actions/checkout@v2
+      with:
+        submodules: 'true'
     - uses: iffy/install-nim@v3
       with:
         version: ${{ matrix.nim }}