bpo-33855: Still more edits and minimal tests for IDLE (GH-7784)

Part 3 of 3, continuing PR #7689. This covers 14 idlelib modules and their tests,
rpc to zoomheight except for run (already done) and tooltip (being done separately).

Lib/idlelib/idle_test/test_warning.py

@@ -5,20 +5,18 @@ This file could be expanded to include traceback overrides
 Revise if output destination changes (http://bugs.python.org/issue18318).
 Make sure warnings module is left unaltered (http://bugs.python.org/issue18081).
 '''
-
+from idlelib import run
+from idlelib import pyshell as shell
 import unittest
 from test.support import captured_stderr
-
 import warnings
+
 # Try to capture default showwarning before Idle modules are imported.
 showwarning = warnings.showwarning
 # But if we run this file within idle, we are in the middle of the run.main loop
 # and default showwarnings has already been replaced.
 running_in_idle = 'idle' in showwarning.__name__
 
-from idlelib import run
-from idlelib import pyshell as shell
-
 # The following was generated from pyshell.idle_formatwarning
 # and checked as matching expectation.
 idlemsg = '''
@@ -29,6 +27,7 @@ UserWarning: Test
 '''
 shellmsg = idlemsg + ">>> "
 
+
 class RunWarnTest(unittest.TestCase):
 
     @unittest.skipIf(running_in_idle, "Does not work when run within Idle.")
@@ -46,6 +45,7 @@ class RunWarnTest(unittest.TestCase):
             # The following uses .splitlines to erase line-ending differences
             self.assertEqual(idlemsg.splitlines(), f.getvalue().splitlines())
 
+
 class ShellWarnTest(unittest.TestCase):
 
     @unittest.skipIf(running_in_idle, "Does not work when run within Idle.")
@@ -70,4 +70,4 @@ class ShellWarnTest(unittest.TestCase):
 
 
 if __name__ == '__main__':
-    unittest.main(verbosity=2, exit=False)
+    unittest.main(verbosity=2)