diff --git a/.github/workflows/macos.yml b/.github/workflows/macos.yml
index b3f68d3..8fc351e 100644
--- a/.github/workflows/macos.yml
+++ b/.github/workflows/macos.yml
@@ -13,7 +13,7 @@ jobs:
   build:
     name: Build and upload artefact
     strategy:
-      max-parallel: 1
+      # max-parallel: 1
       matrix:
         os: [macos-latest, macos-13]
         python-version: ["3.8", "3.9", "3.10", "3.11"]
@@ -107,7 +107,7 @@ jobs:
     name: Test the wheel
     needs: build
     strategy:
-      max-parallel: 1
+      # max-parallel: 1
       matrix:
         os: [macos-latest, macos-13]
         python-version: ["3.8", "3.9", "3.10", "3.11"]
@@ -130,6 +130,8 @@ jobs:
         echo "_PYTHON_HOST_PLATFORM=${_PYTHON_HOST_PLATFORM}" >> $GITHUB_ENV
         PYTHON_VERSION_STR=$(python -c "import sys;print(f'cp{sys.version_info.major}{sys.version_info.minor}')")
         echo "PYTHON_VERSION_STR=${PYTHON_VERSION_STR}" >> $GITHUB_ENV
+        SAMSEG_TEST_PATH=${GITHUB_WORKSPACE}/samseg
+        echo "SAMSEG_TEST_PATH=${SAMSEG_TEST_PATH}" >> $GITHUB_ENV
 
     - name: Detect if x64 and set build variables
       if: runner.arch == 'x64'
@@ -138,6 +140,8 @@ jobs:
         echo "_PYTHON_HOST_PLATFORM=${_PYTHON_HOST_PLATFORM}" >> $GITHUB_ENV
         PYTHON_VERSION_STR=$(python -c "import sys;print(f'cp{sys.version_info.major}{sys.version_info.minor}')")
         echo "PYTHON_VERSION_STR=${PYTHON_VERSION_STR}" >> $GITHUB_ENV
+        SAMSEG_TEST_PATH=${GITHUB_WORKSPACE}/samseg
+        echo "SAMSEG_TEST_PATH=${SAMSEG_TEST_PATH}" >> $GITHUB_ENV
 
     - name: Download artifact
       uses: actions/download-artifact@v4
@@ -151,7 +155,7 @@ jobs:
         python -m pip install samseg*.whl
         python -m pip install pytest
         python -m pip install tensorflow
-        python -m pytest samseg
+        pytest --pyargs samseg.tests
 
   publish:
     name: Publish the wheel
diff --git a/samseg/tests/test_samseg.py b/samseg/tests/test_samseg.py
index f2e1d67..b5827ee 100644
--- a/samseg/tests/test_samseg.py
+++ b/samseg/tests/test_samseg.py
@@ -12,6 +12,17 @@
 from ..Samseg import initVisualizer, Samseg
 from ..io import kvlReadSharedGMMParameters
 
+# This is a hack to test an installed wheel
+# Because the test data is not in the wheel
+# the tests would fail. If you export the
+# SAMSEG_TEST_PATH variable to point to
+# the source code directory, the test data
+# is picked up from there instead.
+try:
+    SAMSEGDIR = os.environ['SAMSEG_TEST_PATH']
+except KeyError:
+    print("No environment variable set, using standard path.")
+
 @pytest.fixture(scope='module')
 def testernie_nii():
     fn = os.path.join(