Fixed multi-thread connection initialization for ZPsycopgDA.

The connection initialization (transaction isolation, typecasts) was
only done for first connection. When there are multiple threads running
in parallel, connections where used which had not been initialized
correctly.

ZPsycopgDA/test_da.py

@@ -0,0 +1,42 @@
+# zopectl run script to test the DA/threading behavior
+#
+# Usage: bin/zopectl run test_da.py "dbname=xxx"
+#
+from Products.ZPsycopgDA.DA import ZDATETIME
+from Products.ZPsycopgDA.db import DB
+import sys
+import threading
+
+
+dsn = sys.argv[1]
+
+
+typecasts = [ZDATETIME]
+
+
+def DA_connect():
+    db = DB(dsn, tilevel=2, typecasts=typecasts)
+    db.open()
+    return db
+
+
+def assert_casts(conn, name):
+    connection = conn.getcursor().connection
+    if (connection.string_types ==
+            {1114: ZDATETIME, 1184: ZDATETIME}):
+        print '%s pass\n' % name
+    else:
+        print '%s fail (%s)\n' % (name, connection.string_types)
+
+
+def test_connect(name):
+    assert_casts(conn1, name)
+
+
+conn1 = DA_connect()
+t1 = threading.Thread(target=test_connect, args=('t1',))
+t1.start()
+t2 = threading.Thread(target=test_connect, args=('t2',))
+t2.start()
+t1.join()
+t2.join()