Fixed the infinite running error

Removed some old stale files in the resources folder

There is an infinite loop in `session._begin_tx` method where a tx is created before a conn is really established.
As a result, if the server went down before the session is closed, then in `session._close`, the session will see a tx should be rolled back and blocks infinitly on `tx._roll_back.consume` as no record will ever return.
This PR makes sure that in `session._begin_tx`, a tx is created after a conn is established.

Author: Zhen

neo4j/bolt/connection.py

@@ -458,6 +458,8 @@ def connect(address, ssl_context=None, **config):
             raise ServiceUnavailable("Failed to establish connection to {!r}".format(address))
         else:
             raise
+    except ConnectionResetError:
+        raise ServiceUnavailable("Failed to establish connection to {!r}".format(address))
 
     # Secure the connection if an SSL context has been provided
     if ssl_context and SSL_AVAILABLE:
@@ -500,7 +502,10 @@ def connect(address, ssl_context=None, **config):
     ready_to_read, _, _ = select((s,), (), (), 0)
     while not ready_to_read:
         ready_to_read, _, _ = select((s,), (), (), 0)
-    data = s.recv(4)
+    try:
+        data = s.recv(4)
+    except ConnectionResetError:
+        raise ServiceUnavailable("Failed to read any data from server {!r} after connected".format(address))
     data_size = len(data)
     if data_size == 0:
         # If no data is returned after a successful select

neo4j/v1/api.py

@@ -425,8 +425,8 @@ def _run_transaction(self, access_mode, unit_of_work, *args, **kwargs):
         t0 = t1 = time()
         while t1 - t0 <= self._max_retry_time:
             try:
-                self._create_transaction()
                 self._connect(access_mode)
+                self._create_transaction()
                 self.__begin__()
                 with self._transaction as tx:
                     return unit_of_work(tx, *args, **kwargs)

test/examples/base_application.py

@@ -25,4 +25,4 @@ def __init__(self, uri, user, password):
         self._driver = GraphDatabase.driver( uri, auth=( user, password ) )
 
     def close(self):
-        self._driver.close();
+        self._driver.close()

test/examples/service_unavailable_example.py

@@ -33,6 +33,6 @@ def addItem(self):
         try:
             session.write_transaction(lambda tx: tx.run("CREATE (a:Item)"))
             return True
-        except ServiceUnavailable as e:
+        except ServiceUnavailable:
             return False
     # end::service-unavailable[]