Issue python#117: test suite: fix test cases with runAll.py option -R:

This commit fixes problems in the Stackless test suite at Python level. It does not fix failures caused by reference leaks.
- Fix failures, which occurred during a second or further run of the test.
- Mark test-cases, which inevitably leak references. These tests leave a C-stack without thread. No chance to clean the references.

https://bitbucket.org/stackless-dev/stackless/issues/117
(grafted from 7ae818842aa4783eb33be6a6085535ba18db97bc)

Author: Anselm Kruis

Stackless/unittests/test_miscell.py

@@ -20,7 +20,7 @@
     withThreads = False
 
 from support import test_main  # @UnusedImport
-from support import StacklessTestCase, AsTaskletTestCase, require_one_thread
+from support import StacklessTestCase, AsTaskletTestCase, require_one_thread, testcase_leaks_references
 
 
 def is_soft():
@@ -613,18 +613,22 @@ def other_thread_main():
             tlet.kill()
 
     @unittest.skipUnless(withThreads, "requires thread support")
+    @testcase_leaks_references("chatches TaskletExit and does not die in its own thread", soft_switching=False)
     def test_kill_without_thread_state_nl0(self):
         return self._test_kill_without_thread_state(0, False)
 
     @unittest.skipUnless(withThreads, "requires thread support")
+    @testcase_leaks_references("chatches TaskletExit and does not die in its own thread")
     def test_kill_without_thread_state_nl1(self):
         return self._test_kill_without_thread_state(1, False)
 
     @unittest.skipUnless(withThreads, "requires thread support")
+    @testcase_leaks_references("chatches TaskletExit and does not die in its own thread", soft_switching=False)
     def test_kill_without_thread_state_blocked_nl0(self):
         return self._test_kill_without_thread_state(0, True)
 
     @unittest.skipUnless(withThreads, "requires thread support")
+    @testcase_leaks_references("chatches TaskletExit and does not die in its own thread")
     def test_kill_without_thread_state_blocked_nl1(self):
         return self._test_kill_without_thread_state(1, True)
 
@@ -1098,6 +1102,7 @@ def test():
         self.assertEqual(self.recursion_depth_in_test, 1)
 
     @unittest.skipUnless(withThreads, "requires thread support")
+    @testcase_leaks_references("Tasklet chatches TaskletExit and refuses to die in its thread")
     def test_unbind_fail_cstate_no_thread(self):
         # https://bitbucket.org/stackless-dev/stackless/issues/92
         loop = True
@@ -1257,6 +1262,10 @@ def test_nesting_level(self):
         self.assertIsInstance(l1, int)
 
     def test_chain(self):
+        # create at least one additional C-stack
+        t = stackless.tasklet(apply_not_stackless)(stackless.main.switch,)
+        t.run()
+        self.addCleanup(t.run)
         start = stackless.main.cstate
         c = start.next
         self.assertIsNot(c, start)

Stackless/unittests/test_pickle.py

@@ -567,11 +567,13 @@ def b():
         def c():
             return b()
 
-        try:
-            c()
-        except ZeroDivisionError:
-            tb = sys.exc_info()[2]
+        def d():
+            try:
+                c()
+            except ZeroDivisionError:
+                return sys.exc_info()[2]
 
+        tb = d()  # this way tb dosn't reference the current frame
         innerframes_orig = inspect.getinnerframes(tb)
         p = self.dumps(tb)
         tb2 = self.loads(p)

Stackless/unittests/test_thread.py

@@ -8,7 +8,7 @@
 from stackless import _test_nostacklesscall as apply_not_stackless
 
 from support import test_main  # @UnusedImport
-from support import StacklessTestCase, AsTaskletTestCase
+from support import StacklessTestCase, AsTaskletTestCase, testcase_leaks_references
 try:
     import threading
     try:
@@ -18,6 +18,7 @@
     withThreads = True
 except:
     withThreads = False
+
     class threading(object):
         Thread = object
 
@@ -400,6 +401,7 @@ def test_rebind_from_dead(self):
         t.bind_thread()
         self.assertEqual(t.thread_id, stackless.getcurrent().thread_id)
 
+    @testcase_leaks_references("test catches TaskletExit and refuses to die in its own thread")
     def test_rebind_from_dead_fail_cstate(self):
         # A test for https://bitbucket.org/stackless-dev/stackless/issues/92
         loop = True

Stackless/unittests/test_tpflags_have_stackless_call.py

@@ -252,14 +252,18 @@ def func(obj=None):
             obj.nesting_level = stackless.current.nesting_level
             return None
 
+        cls(func).__class__  # the first access of __class__ releases 1 ref to None
         with stackless.atomic():
-            # None-refcount it needs protection, it the test suite is multithreaded
+            # None-refcount needs protection, it the test suite is multithreaded
             gc.collect()
-            rc_none = sys.getrefcount(None)
-            rc_cls = sys.getrefcount(cls)
+            rc_none = rc_none2 = sys.getrefcount(None)
+            rc_cls = rc_cls2 = sys.getrefcount(cls)
             c = cls(func)
-            self.assertEqual(sys.getrefcount(None), rc_none)
-            self.assertEqual(sys.getrefcount(c) - sys.getrefcount(object()), 1)
+            rc_none2 = sys.getrefcount(None)
+            rc_cls2 = sys.getrefcount(cls)
+        self.assertEqual(rc_none, rc_none2)
+        self.assertEqual(rc_cls + 1, rc_cls2)  # one ref for c
+        self.assertEqual(sys.getrefcount(c) - sys.getrefcount(object()), 1)
         self.assertIs(c.__class__, cls)
         current_nesting_level = stackless.current.nesting_level
         if hasattr(c, "nesting_level"):
@@ -328,6 +332,7 @@ def helper():
                 return emsg
             self.fail("does not raise the expected exception")
 
+        helper()  # warm up.
         gc.collect()
         with stackless.atomic():
             rc_none = sys.getrefcount(None)
@@ -367,6 +372,7 @@ def helper():
             self.fail("does not raise the expected exception")
 
         emsg = ''
+        helper()  # warm up
         gc.collect()
         with stackless.atomic():
             rc_none = sys.getrefcount(None)

Stackless/unittests/test_watchdog.py

@@ -521,7 +521,8 @@ def runner_func():
 
     def _test_watchdog_on_tasklet(self, soft):
         def runner_func():
-            stackless.run(2, soft=soft, totaltimeout=True, ignore_nesting=True)
+            # run the watchdog long enough to start t1 and t2
+            stackless.run(150, soft=soft, totaltimeout=True, ignore_nesting=True)
             if stackless.getruncount():
                 self.done += 1  # we were interrupted
             t1.kill()