Issue #20567: Delete class attribute gui widgets in idle tests.

Code patch by Serhiy Storchaka

5 files changed, 13 insertions, 3 deletions

diff --git a/Lib/idlelib/idle_test/README.txt b/Lib/idlelib/idle_test/README.txt
index d0dde25..6b92483 100644
--- a/Lib/idlelib/idle_test/README.txt
+++ b/Lib/idlelib/idle_test/README.txt
@@ -41,9 +41,10 @@ idle class. For the benefit of buildbot machines that do not have a graphics
 screen, gui tests must be 'guarded' by "requires('gui')" in a setUp
 function or method. This will typically be setUpClass.
 
-All gui objects must be destroyed by the end of the test, perhaps in a tearDown
-function. Creating the Tk root directly in a setUp allows a reference to be saved
-so it can be properly destroyed in the corresponding tearDown. 
+To avoid interfering with other gui tests, all gui objects must be destroyed
+and deleted by the end of the test.  If a widget, such as a Tk root, is created
+in a setUpX function, destroy it in the corresponding tearDownX.  For module
+and class attributes, also delete the widget.
 ---
     @classmethod
     def setUpClass(cls):
@@ -53,6 +54,7 @@ so it can be properly destroyed in the corresponding tearDown.
     @classmethod
     def tearDownClass(cls):
         cls.root.destroy()
+        del cls.root
 ---
 
 Support.requires('gui') returns true if it is either called in a main module
diff --git a/Lib/idlelib/idle_test/test_formatparagraph.py b/Lib/idlelib/idle_test/test_formatparagraph.py
index 818c9d4..f4a7c2d 100644
--- a/Lib/idlelib/idle_test/test_formatparagraph.py
+++ b/Lib/idlelib/idle_test/test_formatparagraph.py
@@ -277,6 +277,9 @@ class FormatEventTest(unittest.TestCase):
     @classmethod
     def tearDownClass(cls):
         cls.root.destroy()
+        del cls.root
+        del cls.text
+        del cls.formatter
 
     def test_short_line(self):
         self.text.insert('1.0', "Short line\n")
diff --git a/Lib/idlelib/idle_test/test_idlehistory.py b/Lib/idlelib/idle_test/test_idlehistory.py
index b27db91..d7c3d70 100644
--- a/Lib/idlelib/idle_test/test_idlehistory.py
+++ b/Lib/idlelib/idle_test/test_idlehistory.py
@@ -80,6 +80,7 @@ class FetchTest(unittest.TestCase):
     @classmethod
     def tearDownClass(cls):
         cls.root.destroy()
+        del cls.root
 
     def fetch_test(self, reverse, line, prefix, index, *, bell=False):
         # Perform one fetch as invoked by Alt-N or Alt-P
diff --git a/Lib/idlelib/idle_test/test_searchengine.py b/Lib/idlelib/idle_test/test_searchengine.py
index fdf38bd..129a5a3 100644
--- a/Lib/idlelib/idle_test/test_searchengine.py
+++ b/Lib/idlelib/idle_test/test_searchengine.py
@@ -64,6 +64,7 @@ class GetSelectionTest(unittest.TestCase):
 ##    @classmethod
 ##    def tearDownClass(cls):
 ##        cls.root.destroy()
+##        del cls.root
 
     def test_get_selection(self):
         # text = Text(master=self.root)
@@ -219,6 +220,7 @@ class SearchTest(unittest.TestCase):
 ##    @classmethod
 ##    def tearDownClass(cls):
 ##        cls.root.destroy()
+##        del cls.root
 
     def test_search(self):
         Equal = self.assertEqual
@@ -261,6 +263,7 @@ class ForwardBackwardTest(unittest.TestCase):
 ##    @classmethod
 ##    def tearDownClass(cls):
 ##        cls.root.destroy()
+##        del cls.root
 
     @classmethod
     def setUpClass(cls):
diff --git a/Lib/idlelib/idle_test/test_text.py b/Lib/idlelib/idle_test/test_text.py
index 367bf38..5ac2fd7 100644
--- a/Lib/idlelib/idle_test/test_text.py
+++ b/Lib/idlelib/idle_test/test_text.py
@@ -221,6 +221,7 @@ class TkTextTest(TextTest, unittest.TestCase):
     @classmethod
     def tearDownClass(cls):
         cls.root.destroy()
+        del cls.root
 
 
 if __name__ == '__main__':