diff --git a/.github/workflows/test_build.yml b/.github/workflows/test_build.yml
index 3fee61cb..8319c14f 100644
--- a/.github/workflows/test_build.yml
+++ b/.github/workflows/test_build.yml
@@ -32,7 +32,7 @@ jobs:
         run: pip install --upgrade pip
 
       - name: Install deps
-        run: pip install numpy
+        run: pip install numpy cython
 
       - name: Installing package
         run: pip install -e .