Handle regex syntax FutureWarnings.

Make sure they are converted to errors in test runs, to catch
new introductions immediately.

1 files changed, 4 insertions, 0 deletions

diff --git a/tests/run.py b/tests/run.py
index 07665b2a..bdaceb7e 100644
--- a/tests/run.py
+++ b/tests/run.py
@@ -16,6 +16,7 @@ from __future__ import print_function
 
 import os
 import sys
+import warnings
 
 # only find tests in this directory
 if os.path.dirname(__file__):
@@ -31,6 +32,9 @@ except ImportError:
 # make sure the current source is first on sys.path
 sys.path.insert(0, '..')
 
+# make FutureWarnings (coming from Regex syntax most likely) an error
+warnings.filterwarnings("error", category=FutureWarning)
+
 if '--with-coverage' not in sys.argv:
     # if running with coverage, pygments should not be imported before coverage
     # is started, otherwise it will count already executed lines as uncovered