Add CentOS7 docker container
diff --git a/tests/dockerfiles/CentOS_7_pygtk2.patch b/tests/dockerfiles/CentOS_7_pygtk2.patch
new file mode 100644
index 0000000..a5ed29c
--- /dev/null
+++ b/tests/dockerfiles/CentOS_7_pygtk2.patch
@@ -0,0 +1,30 @@
+--- /usr/lib64/python2.7/site-packages/gtk-2.0/gtk/__init__.py 2018-04-23 17:29:19.555209060 +0000
++++ /usr/lib64/python2.7/site-packages/gtk-2.0/gtk/__init__.py 2018-04-23 17:32:53.448304174 +0000
+@@ -47,14 +47,19 @@
+ def _init():
+ import sys
+
+- sys_path = sys.path[:]
++ try:
++ sys_path = sys.path[:]
+
+- _gtk.init_check()
+-
+- # init_check calls PySys_SetArgv which calls sys.path.insert(0, ''),
+- # which causes problems for pychecker, restore it if modified.
+- if sys.path != sys_path:
+- sys.path[:] = sys_path
++ try:
++ _gtk.init_check()
++ except RuntimeError, e:
++ import warnings
++ warnings.warn(str(e), _gtk.Warning)
++ finally:
++ # init_check calls PySys_SetArgv which calls sys.path.insert(0, ''),
++ # which causes problems for pychecker, restore it if modified.
++ if sys.path != sys_path:
++ sys.path[:] = sys_path
+
+ # install the default log handlers
+ _gtk.add_log_handlers()
+