bigfile/tests: move NotifyChannel to test_thread.py

NotifyChannel was introduced in c7c01ce4 (bigfile/zodb: ZODB.Connection
can migrate between threads on close/open and we have to care) to test
thread interaction specific to ZODB.

We'll however need NotifyChannel to do more threading test of virtmem
core, and this way the proper place for NotifyChannel is test_thread.py
itself.

Move it.

bigarray/tests/test_arrayzodb.py

@@ -16,7 +16,8 @@
 #
 # See COPYING file for full licensing terms.
 from wendelin.bigarray.array_zodb import ZBigArray
-from wendelin.bigfile.tests.test_filezodb import kkey, cacheInfo, NotifyChannel, ram_reclaim_all
+from wendelin.bigfile.tests.test_filezodb import kkey, cacheInfo, ram_reclaim_all
+from wendelin.bigfile.tests.test_thread import NotifyChannel
 from wendelin.lib.zodb import dbclose
 from wendelin.lib.testing import getTestDB
 from persistent import UPTODATE

bigfile/tests/test_filezodb.py

@@ -17,6 +17,7 @@
 # See COPYING file for full licensing terms.
 from wendelin.bigfile.file_zodb import LivePersistent, ZBigFile, ZBlk_fmt_registry
 from wendelin.bigfile import file_zodb, ram_reclaim
+from wendelin.bigfile.tests.test_thread import NotifyChannel
 from wendelin.lib.zodb import dbclose
 from wendelin.lib.testing import getTestDB
 from persistent import UPTODATE, GHOST, CHANGED
@@ -343,33 +344,6 @@ def test_bigfile_filezodb():
 
 
 
-# Notify channel for
-#   - one thread to     .wait('condition'), until
-#   - other thread does .tell('condition')
-class NotifyChannel:
-
-    def __init__(self):
-        self.state = None
-
-    def tell(self, condition):
-        #print >>sys.stderr, '  tell %s\tthread_id: %s\n'    \
-        #        % (condition, _thread.get_ident()),
-        # wait until other thread reads previous tell
-        while self.state is not None:
-            pass
-
-        self.state = condition
-
-    def wait(self, condition):
-        #print >>sys.stderr, '  wait %s\tthread_id: %s\n'    \
-        #        % (condition, _thread.get_ident()),
-        while self.state != condition:
-            pass
-        #print >>sys.stderr, '  have %s\tthread_id: %s\n'    \
-        #        % (condition, _thread.get_ident()),
-        self.state = None
-
-
 # connection can migrate between threads handling requests.
 # verify _ZBigFileH properly adjusts.
 # ( NOTE this test is almost dupped at test_zbigarray_vs_conn_migration() )

bigfile/tests/test_thread.py

@@ -20,6 +20,34 @@ from threading import Thread
 from time import sleep
 
 from wendelin.bigfile.tests.test_basic import bchr_py2
+from six.moves import _thread
+
+# Notify channel for
+#   - one thread to     .wait('condition'), until
+#   - other thread does .tell('condition')
+class NotifyChannel:
+
+    def __init__(self):
+        self.state = None
+
+    def tell(self, condition):
+        #print >>sys.stderr, '  tell %s\tthread_id: %s\n'    \
+        #        % (condition, _thread.get_ident()),
+        # wait until other thread reads previous tell
+        while self.state is not None:
+            pass
+
+        self.state = condition
+
+    def wait(self, condition):
+        #print >>sys.stderr, '  wait %s\tthread_id: %s\n'    \
+        #        % (condition, _thread.get_ident()),
+        while self.state != condition:
+            pass
+        #print >>sys.stderr, '  have %s\tthread_id: %s\n'    \
+        #        % (condition, _thread.get_ident()),
+        self.state = None
+
 
 
 # Synthetic bigfile that verifies there is no concurrent calls to loadblk