Issue #18103: Update README.txt and test_idle to describe and run gui tests.
diff --git a/Lib/test/test_idle.py b/Lib/test/test_idle.py
index 9eeb4e2..4262aa3 100644
--- a/Lib/test/test_idle.py
+++ b/Lib/test/test_idle.py
@@ -10,5 +10,10 @@
 load_tests = idletest.load_tests
 
 if __name__ == '__main__':
+    # Until unittest supports resources, we emulate regrtest's -ugui
+    # so loaded tests run the same as if textually present here.
+    # If any Idle test ever needs another resource, add it to the list.
+    from test import support
+    support.use_resources = ['gui']  # use_resources is initially None
     import unittest
     unittest.main(verbosity=2, exit=False)