Issue #15392: Create a unittest framework for IDLE.

Preliminary patch by Rajagopalasarma Jayakrishnan.

Lib/test/test_idle.py

@@ -0,0 +1,14 @@
+# Skip test if tkinter wasn't built or idlelib was deleted.
+from test.support import import_module
+import_module('tkinter')  # discard return
+itdir = import_module('idlelib.idle_test')
+
+# Without test_main present, regrtest.runtest_inner (line1219)
+# imitates unittest.main by calling
+# unittest.TestLoader().loadTestsFromModule(this_module)
+# which look for load_tests and uses it if found.
+load_tests = itdir.load_tests
+
+if __name__ == '__main__':
+    import unittest
+    unittest.main(verbosity=2, exit=False)