diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index a7a9980..6c704ee 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -30,5 +30,4 @@ jobs:
 
     - name: Run Pytest
       run: |
-        export PYTHONPATH=src:$PYTHONPATH
         pytest
diff --git a/tests/conftest.py b/tests/conftest.py
new file mode 100644
index 0000000..cc4ec91
--- /dev/null
+++ b/tests/conftest.py
@@ -0,0 +1,21 @@
+import pytest
+
+
+def pytest_addoption(parser):
+    parser.addoption(
+        "--runslow", action="store_true", default=False, help="run slow tests"
+    )
+
+
+def pytest_configure(config):
+    config.addinivalue_line("markers", "slow: mark test as slow to run")
+
+
+def pytest_collection_modifyitems(config, items):
+    if config.getoption("--runslow"):
+        # --runslow given in cli: do not skip slow tests
+        return
+    skip_slow = pytest.mark.skip(reason="need --runslow option to run")
+    for item in items:
+        if "slow" in item.keywords:
+            item.add_marker(skip_slow)
\ No newline at end of file
diff --git a/tests/test_vip_utils.py b/tests/test_vip_utils.py
index 683ec04..b8639b8 100644
--- a/tests/test_vip_utils.py
+++ b/tests/test_vip_utils.py
@@ -27,6 +27,7 @@ def setup_teardown_vip_launcher():
     yield
     assert delete_path(BASE_PATH_VIP)
 
+@pytest.mark.slow
 def test_upload_download():
     assert upload(BASE_PATH_LOCAL + 'file.txt', BASE_PATH_VIP + 'file.txt')
     assert exists(BASE_PATH_VIP + 'file.txt')
@@ -34,7 +35,7 @@ def test_upload_download():
     assert compare_files(BASE_PATH_LOCAL + 'file.txt', BASE_PATH_LOCAL + 'file_copy.txt')
     assert delete_path(BASE_PATH_VIP + 'file.txt')
 
-
+@pytest.mark.slow
 def test_init_exec():
     input_values = {
         'mand_text': 'value1',
@@ -44,7 +45,7 @@ def test_init_exec():
     exec_info = execution_info(exec_id)
     assert exec_info['status'] == 'Running'
 
-
+@pytest.mark.slow
 def test_kill_exec():
     input_values = {
         'mand_text': 'value1',
@@ -65,6 +66,7 @@ def test_kill_exec():
         if counter > 100:
             raise Exception("Execution not ended after delay")
 
+@pytest.mark.slow
 def test_get_exec_stdout():
     input_values = {
         'mand_text': 'value1',
@@ -80,7 +82,7 @@ def test_get_exec_stdout():
     stdout = get_exec_stdout(exec_id)
     assert isinstance(stdout, str)
     
-
+@pytest.mark.slow
 def test_get_exec_results():
     input_values = {
         'mand_text': 'value1',
@@ -101,7 +103,7 @@ def test_get_exec_results():
         assert 'executionId' in r
         assert 'path' in r
     
-
+@pytest.mark.slow
 def test_list_pipeline():
     pipelines = list_pipeline()
     # assert that this is a list of dictionaries
@@ -115,7 +117,7 @@ def test_list_pipeline():
         assert 'canExecute' in p
         assert 'description' in p
 
-
+@pytest.mark.slow
 def test_pipeline_def():
     pipeline = pipeline_def('CQUEST/0.3')
     assert isinstance(pipeline, dict)
@@ -126,7 +128,7 @@ def test_pipeline_def():
     assert 'canExecute' in pipeline
     assert 'description' in pipeline
 
-
+@pytest.mark.slow
 def test_platform_info():
     info = platform_info()
     assert isinstance(info, dict)