--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/common-pattern.py	Sun Nov 05 06:41:38 2017 +0100
@@ -0,0 +1,9 @@
+# common patterns in test at can safely be replaced
+from __future__ import absolute_import
+
+substitutions = [
+    # list of possible compressions
+    (br'zstd,zlib,none,bzip2',
+     br'$USUAL_COMPRESSIONS$'
+    ),
+]