diff --git a/.github/workflows/commit.yml b/.github/workflows/commit.yml
index c9600a744..cdefd9cf0 100644
--- a/.github/workflows/commit.yml
+++ b/.github/workflows/commit.yml
@@ -109,7 +109,7 @@ jobs:
     env:
       PYTHON_VERSION: 3.8
     strategy:
-      fail-fast: true
+      fail-fast: false
       matrix:
         optdeps:
           - "all optional dependencies"
@@ -132,6 +132,10 @@ jobs:
           pip install --upgrade pip
           pip install .
           pip install ".[test]"
+
+          # Install optional dependencies according to matrix.optdeps.
+          # If matrix.optdeps is "some" remove 3 optional dependencies
+          # selected randomly using the current date as the seed.
           if [[ ! "${{ matrix.optdeps }}" == *"no"* ]]; then
             pip install ".[optional]"
           fi
diff --git a/autotest/test_mf6.py b/autotest/test_mf6.py
index 9774a775b..f9b475a4a 100644
--- a/autotest/test_mf6.py
+++ b/autotest/test_mf6.py
@@ -637,7 +637,7 @@ def test_binary_write(function_tmpdir, layered):
 
 
 @requires_exe("mf6")
-@requires_pkg("shapely")
+@requires_pkg("shapely", "scipy")
 @pytest.mark.parametrize("layered", [True, False])
 def test_vor_binary_write(function_tmpdir, layered):
     # build voronoi grid