Add pytest markers for slow tests

Author: twizmwazin

pytest.ini

@@ -0,0 +1,8 @@
+[pytest]
+minversion = 6.0
+markers = 
+    slow: mark test as too slow to run in every CI run
+
+testpaths = 
+    tests
+

tests/test_examples.py

@@ -3,10 +3,12 @@
 import subprocess
 from unittest import skipIf
 
+import pytest
 from flaky import flaky
 
 
 def slow_test(func):
+    pytest.mark.slow(func)
     func.speed = "slow"
     slow_test_env = (
         os.environ["SKIP_SLOW_TESTS"].lower()