diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index ca93812..55edb47 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -60,7 +60,7 @@ jobs:
         run: |
           pip install Cython==0.29.18
           pip install moments-popgen
-        if: !(runner.os == 'MacOS' && matrix.python-version == '3.8')
+        if: runner.os != 'MacOS' || matrix.python-version != '3.8'
 
       - name: Install GADMA and its dependencies.
         run: |