Testing: Detect --run-slow option when passed to runtests.py

runtests.py

@@ -10,6 +10,7 @@
 
 # Standard library imports
 import os
+import sys
 
 # Third party imports
 import qtpy  # to ensure that Qt4 uses API v2
@@ -18,10 +19,9 @@
 
 # To run our slow tests only in our CIs
 run_slow = False
-if os.environ.get('CI', None) is not None:
+if os.environ.get('CI', None) is not None or '--run-slow' in sys.argv:
     run_slow = True
 
-
 def main():
     """
     Run pytest tests.