diff --git a/tests/test_graph.py b/tests/test_graph.py
index bd5e8c8..61db667 100644
--- a/tests/test_graph.py
+++ b/tests/test_graph.py
@@ -2,12 +2,16 @@
 from macrogen.config import config
 import pytest
 
+
 @pytest.fixture('session')
+@pytest.mark.slow
 def eades_graphs():
     config.fes_method = 'eades'
     config.lightweight_timeline = False
     return macrogen.graph.MacrogenesisInfo()
 
+
+@pytest.mark.slow
 def test_conflict_info(eades_graphs):
     cs = eades_graphs.conflict_stats()
-    assert cs
\ No newline at end of file
+    assert cs
diff --git a/tests/test_witnesses.py b/tests/test_witnesses.py
index 28c57b4..5194591 100644
--- a/tests/test_witnesses.py
+++ b/tests/test_witnesses.py
@@ -1,5 +1,6 @@
 from pathlib import Path
 
+import pytest
 from macrogen import witnesses, config
 from macrogen.witnesses import SceneInfo, WitInscrInfo
 
@@ -9,6 +10,8 @@ def test_document():
     assert doc.sigil == '2 H'
     assert doc.uri == 'faust://document/faustedition/2_H'
 
+
+@pytest.mark.slow
 def test_all_documents():
     docs = witnesses.all_documents()
     assert docs
@@ -19,5 +22,7 @@ def test_scenes():
     assert si.toplevel[0].n == '1.0.1'
     assert si.scenes[-1].n == '2.5.5'
 
+
+@pytest.mark.slow
 def test_witinfo():
     wi = WitInscrInfo.get()