Merge lp:~therve/storm/twisted-integration into lp:storm

[Christopher Armstrong]

[Christopher Armstrong (radix)]

[1] Why setDaemon(True)

[2] can you use underscores for DeferredStore

[3] doc for get explaining that it loads all attributes

[4] It may be useful to extend the core Store API to allow us to avoid accessing internal attributes in the wrapper. Like, for example, Store.disable_lazy_loading(). I dunno.

[5] global mapping of storm store to deferred store? maybe?

[6] Make it so that objects that came from stores which were then put back into a pool are "broken" so that any attribute access breaks in the future.

review: Abstain

[Gabriel (gabriel-rossetti)]

Christopher Armstrong wrote:
> Christopher Armstrong has proposed merging lp:~therve/storm/twisted-integration into lp:storm.
>
> Requested reviews:
> Storm Developers (storm)
>
I second that :-)

Gabriel

[Christopher Armstrong (radix)]

[7] Expose reload to DeferredStore

[8] Maybe add deferredStore.commit(reload=True)

review: Abstain

[Drew Smathers (djfroofy)]

> [4] It may be useful to extend the core Store API to allow us to avoid accessing internal attributes in the wrapper. Like, for example, Store.disable_lazy_loading(). I dunno.

That sounds like a great idea to me. Otherwise having to refetch objects just to avoid lazy value errors in less than ideal.

[lp:~therve/storm/twisted-integration]

215. By Thomas Herve on 2009-02-19

Merge from trunk.

216. By Thomas Herve on 2009-02-19

Move the tests to be able to run Postgres/MySQL tests as well

217. By Thomas Herve on 2009-02-19

Add postgres tests

218. By Thomas Herve on 2009-02-19

Add mysql, some tests failing.

219. By Thomas Herve on 2009-02-19

Use InnoDB to be able to use transactions.

220. By Thomas Herve on 2009-05-08

Merge from trunk.

221. By Thomas Herve on 2009-05-08

Force respect of the max_stores value, by incrementing the number of stores
once start_store is called, instead of doing it in the callback [f=373816]

222. By Thomas Herve on 2009-05-14

Use TestHelper/MakePath to manage sqlite file.

223. By Thomas Herve on 2009-06-11

Fix doc typos

224. By Thomas Herve on 2009-10-24

Merge from trunk

225. By Thomas Herve on 2009-12-26

Some tests cleanup

226. By Thomas Herve on 2009-12-26

Merge from trunk

227. By Thomas Herve on 2009-12-26

Cleanups

228. By Thomas Herve on 2009-12-26

Check thread in Connection to catch problems.

229. By Thomas Herve on 2009-12-27

Handle errors in rollback

230. By Thomas Herve on 2009-12-27

Typo, cleanup

231. By Thomas Herve on 2009-12-27

Make start/stop methods private

Unmerged revisions

231. By Thomas Herve on 2009-12-27

Make start/stop methods private

230. By Thomas Herve on 2009-12-27

Typo, cleanup

229. By Thomas Herve on 2009-12-27

Handle errors in rollback

228. By Thomas Herve on 2009-12-26

Check thread in Connection to catch problems.

227. By Thomas Herve on 2009-12-26

Cleanups

226. By Thomas Herve on 2009-12-26

Merge from trunk

225. By Thomas Herve on 2009-12-26

Some tests cleanup

224. By Thomas Herve on 2009-10-24

Merge from trunk

223. By Thomas Herve on 2009-06-11

Fix doc typos

222. By Thomas Herve on 2009-05-14

Use TestHelper/MakePath to manage sqlite file.

=== modified file 'storm/database.py'
--- storm/database.py	2009-07-30 06:19:27 +0000
+++ storm/database.py	2009-12-27 11:31:14 +0000
@@ -24,12 +24,13 @@
 This is the common code for database support; specific databases are
 supported in modules in L{storm.databases}.
 """
+import threading
 
 from storm.expr import Expr, State, compile
 from storm.tracer import trace
 from storm.variables import Variable
 from storm.exceptions import (
-    ClosedError, DatabaseError, DisconnectionError, Error)
+    ClosedError, DatabaseError, DisconnectionError, Error, ThreadSafetyError)
 from storm.uri import URI
 import storm
 
@@ -180,6 +181,20 @@
         self._database = database # Ensures deallocation order.
         self._event = event
         self._raw_connection = self._database.raw_connect()
+        self._thread = threading.currentThread()
+
+    def _check_thread(self):
+        """
+        Check if the current thread is the same thread that created the
+        connection. This is a safety check that prevents breaking thread
+        boundaries which can create weird bugs. C{execute}, C{commit} and
+        C{rollback} should call it, directly or indirectly.
+        """
+        thread = threading.currentThread()
+        if thread is not self._thread:
+            raise ThreadSafetyError(
+                "'%s' is not the connection thread '%s'" %
+                (thread, self._thread))
 
     def __del__(self):
         """Close the connection."""
@@ -240,6 +255,7 @@
 
     def rollback(self):
         """Rollback the connection."""
+        self._check_thread()
         if self._state == STATE_CONNECTED:
             try:
                 self._raw_connection.rollback()
@@ -314,6 +330,7 @@
         If the connection is marked as dead, or if we can't reconnect,
         then raise DisconnectionError.
         """
+        self._check_thread()
         if self._state == STATE_CONNECTED:
             return
         elif self._state == STATE_DISCONNECTED:
 
=== modified file 'storm/exceptions.py'
--- storm/exceptions.py	2009-05-15 08:43:21 +0000
+++ storm/exceptions.py	2009-12-27 11:31:14 +0000
@@ -82,6 +82,10 @@
     pass
 
 
+class ThreadSafetyError(StormError):
+    """Exception raised when cross-threads operations are attempted."""
+
+
 class Error(StormError):
     pass
 
 
=== added directory 'storm/twisted'
=== added file 'storm/twisted/__init__.py'
--- storm/twisted/__init__.py	1970-01-01 00:00:00 +0000
+++ storm/twisted/__init__.py	2009-12-27 11:31:14 +0000
@@ -0,0 +1,23 @@
+#
+# Copyright (c) 2007 Canonical
+# Copyright (c) 2007 Thomas Herve <[e-mail]>
+#
+# This file is part of Storm Object Relational Mapper.
+#
+# Storm is free software; you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as
+# published by the Free Software Foundation; either version 2.1 of
+# the License, or (at your option) any later version.
+#
+# Storm is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+"""
+Asynchronous wrapper around storm to be used within a Twisted application.
+"""
 
=== added file 'storm/twisted/store.py'
--- storm/twisted/store.py	1970-01-01 00:00:00 +0000
+++ storm/twisted/store.py	2009-12-27 11:31:14 +0000
@@ -0,0 +1,480 @@
+#
+# Copyright (c) 2007 Canonical
+# Copyright (c) 2007 Thomas Herve <[e-mail]>
+#
+# This file is part of Storm Object Relational Mapper.
+#
+# Storm is free software; you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as
+# published by the Free Software Foundation; either version 2.1 of
+# the License, or (at your option) any later version.
+#
+# Storm is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+"""
+Store wrapper and custom thread runner.
+"""
+
+from threading import Thread
+from Queue import Queue
+
+from storm.store import Store, AutoReload
+from storm.info import get_obj_info
+from storm.twisted.wrapper import partial, DeferredResult, DeferredResultSet
+
+from twisted.internet.defer import Deferred, deferredGenerator, maybeDeferred
+from twisted.internet.defer import waitForDeferred, succeed, fail
+from twisted.python.failure import Failure
+
+
+
+class AlreadyStopped(Exception):
+    """
+    Except raised when a store is stopped multiple time.
+    """
+
+
+
+class StoreThread(Thread):
+    """
+    A thread class that wraps methods calls and fires deferred in the reactor
+    thread.
+    """
+    STOP = object()
+
+    def __init__(self):
+        """
+        Initialize the thread, and create a L{Queue} to stack jobs.
+        """
+        Thread.__init__(self)
+        self.setDaemon(True)
+        self._queue = Queue()
+        self._stop_deferred = None
+        self.stopped = False
+
+
+    def defer_to_thread(self, f, *args, **kwargs):
+        """
+        Run the given function in the thread, wrapping the result with a
+        L{Deferred}.
+
+        @return: a deferred whose result will be the result of the function.
+        @rtype: C{Deferred}
+        """
+        if self.stopped:
+            # to prevent having pending calls after the thread got stopped
+            return fail(AlreadyStopped(f))
+        d = Deferred()
+        self._queue.put((d, f, args, kwargs))
+        return d
+
+
+    def run(self):
+        """
+        Main execution loop: retrieve jobs from the queue and run them.
+        """
+        from twisted.internet import reactor
+        o = self._queue.get()
+        while o is not self.STOP:
+            d, f, args, kwargs = o
+            try:
+                result = f(*args, **kwargs)
+            except:
+                f = Failure()
+                reactor.callFromThread(d.errback, f)
+            else:
+                reactor.callFromThread(d.callback, result)
+            o = self._queue.get()
+        reactor.callFromThread(self._stop_deferred.callback, None)
+
+
+    def stop(self):
+        """
+        Stop the thread.
+        """
+        if self.stopped:
+            return self._stop_deferred
+        self._stop_deferred = Deferred()
+        self._queue.put(self.STOP)
+        self.stopped = True
+        return self._stop_deferred
+
+
+
+class DeferredStore(object):
+    """
+    A wrapper around L{Store} to have async operations.
+    """
+    store = None
+
+    def __init__(self, database):
+        """
+        @param database: instance of database providing connection, used to
+            instantiate the store later.
+        @type database: L{storm.database.Database}
+        """
+        self.thread = StoreThread()
+        self.database = database
+        self.started = False
+
+
+    def start(self):
+        """
+        Start the store.
+
+        @return: a deferred that will fire once the store is started.
+        """
+        if not self.started:
+            self.started = True
+            self.thread.start()
+            # Add a event trigger to be sure that the thread is stopped
+            from twisted.internet import reactor
+            reactor.addSystemEventTrigger(
+                "before", "shutdown", self.stop)
+            return self.thread.defer_to_thread(Store, self.database
+                ).addCallback(self._got_store)
+        else:
+            raise RuntimeError("Already started")
+
+
+    def _got_store(self, store):
+        """
+        Internal method called when the store is created, initializing most of
+        the API methods.
+        """
+        self.store = store
+        # Maybe not ?
+        self.store._deferredStore = self
+        for methodName in ("commit", "flush", "remove", "reload",
+                           "rollback"):
+            method = partial(self.thread.defer_to_thread,
+                             getattr(self.store, methodName))
+            setattr(self, methodName, method)
+
+        self._do_resolve_lazy_value = self.store._resolve_lazy_value
+        self.store._resolve_lazy_value = self._resolve_lazy_value
+
+
+    def get(self, cls, key):
+        def _get():
+            obj = self.store.get(cls, key)
+            if obj is not None:
+                obj_info = get_obj_info(obj)
+                self._do_resolve_lazy_value(obj_info, None, AutoReload)
+            return obj
+        return self.thread.defer_to_thread(_get)
+
+
+    def add(self, obj):
+        """
+        Specific add method that doesn't return any result, to not make think
+        that it's something usable.
+        """
+        def _add():
+            self.store.add(obj)
+        return self.thread.defer_to_thread(_add)
+
+
+    def execute(self, *args, **kwargs):
+        """
+        Wrapper around C{execute} to have a C{DeferredResult} instead of the
+        standard L{storm.database.Result} object.
+        """
+        if self.store is None:
+            raise RuntimeError("Store not started")
+        return self.thread.defer_to_thread(
+            self.store.execute, *args, **kwargs
+            ).addCallback(self._cb_execute)
+
+
+    def _cb_execute(self, result):
+        """
+        Wrap the result with a C{DeferredResult}.
+        """
+        if result is not None:
+            return DeferredResult(self.thread, result)
+
+
+    def find(self, *args, **kwargs):
+        """
+        Wrapper around C{find}.
+        """
+        if self.store is None:
+            raise RuntimeError("Store not started")
+        return self.thread.defer_to_thread(
+            self.store.find, *args, **kwargs
+            ).addCallback(self._cb_find)
+
+
+    def _cb_find(self, resultSet):
+        """
+        Wrap the result set with a C{DeferredResultSet}.
+        """
+        return DeferredResultSet(self.thread, resultSet)
+
+
+    def stop(self):
+        """
+        Stop the store.
+        """
+        if self.thread.stopped:
+            return succeed(None)
+        def close():
+            self.store.rollback()
+            self.store.close()
+        return self.thread.defer_to_thread(close
+            ).addCallback(lambda ign: self.thread.stop())
+
+
+    def _resolve_lazy_value(self, *args):
+        raise RuntimeError(
+            "Resolving lazy values with the Twisted wrapper is not possible "
+            "right now! Please refetch your object using "
+            "store.get/store.find")
+
+
+    @staticmethod
+    def of(obj):
+        """
+        Get the DeferredStore object is associated with
+
+        If the given object has not been associated with a DeferredStore,
+        return None.
+        """
+        store = Store.of(obj)
+        if not store:
+            return
+        return getattr(store, '_deferredStore', None)
+
+
+
+class StorePool(object):
+    """
+    A pool of started stores, maintaining persistent connections.
+    """
+    started = False
+    store_factory = DeferredStore
+
+    def __init__(self, database, min_stores=0, max_stores=10):
+        """
+        @param database: instance of database providing connection, used to
+            instantiate the store later.
+        @type database: L{storm.database.Database}
+
+        @param min_stores: initial number of stores.
+        @type min_stores: C{int}
+
+        @param max_stores: maximum number of stores.
+        @type max_stores: C{int}
+        """
+        self.database = database
+        self.min_stores = min_stores
+        self.max_stores = max_stores
+        self._stores = []
+        self._stores_created = 0
+        self._pending_get = []
+        self._store_refs = []
+
+
+    def start(self):
+        """
+        Start the pool.
+        """
+        if self.started:
+            raise RuntimeError("Already started")
+        self.started = True
+        return self.adjust_size()
+
+
+    def stop(self):
+        """
+        Stop the pool: this is not a total stop, it just try to kill the
+        current available stores.
+        """
+        return self.adjust_size(0, 0, self._store_refs)
+
+
+    def _start_store(self):
+        """
+        Create a new store.
+        """
+        store = self.store_factory(self.database)
+        # Increment here, so that other simultaneous calls don't make the
+        # number of connections pass the maximum
+        self._stores_created += 1
+        return store.start(
+            ).addCallback(self._cb_start_store, store
+            ).addErrback(self._eb_start_store)
+
+
+    def _cb_start_store(self, ign, store):
+        """
+        Add the created store to the list of available stores.
+        """
+        self._stores.append(store)
+        self._store_refs.append(store)
+
+
+    def _eb_start_store(self, failure):
+        """
+        Reduce the amount of created stores, and let the failure propagate.
+        """
+        self._stores_created -= 1
+        return failure
+
+
+    def _stop_store(self, stores=None):
+        """
+        Stop a store and remove it from the available stores.
+        """
+        if stores is None:
+            stores = self._stores
+        self._stores_created -= 1
+        store = stores.pop()
+        return store.stop()
+
+
+    @deferredGenerator
+    def adjust_size(self, min_stores=None, max_stores=None, stores=None):
+        """
+        Change the number of available stores, shrinking or raising as
+        necessary.
+        """
+        if min_stores is None:
+            min_stores = self.min_stores
+        if max_stores is None:
+            max_stores = self.max_stores
+        if stores is None:
+            stores = self._stores
+
+        if min_stores < 0:
+            raise ValueError('minimum is negative')
+        if min_stores > max_stores:
+            raise ValueError('minimum is greater than maximum')
+
+        self.min_stores = min_stores
+        self.max_stores = max_stores
+        if not self.started:
+            return
+
+        # Kill of some stores if we have too many.
+        while self._stores_created > self.max_stores and stores:
+            wfd = waitForDeferred(self._stop_store(stores))
+            yield wfd
+            wfd.getResult()
+        # Start some stores if we have too few.
+        while self._stores_created < self.min_stores:
+            wfd = waitForDeferred(self._start_store())
+            yield wfd
+            wfd.getResult()
+
+
+    def get(self):
+        """
+        Return a started store from the pool, or start a new one if necessary.
+        A store retrieve by this way should be put back using the put
+        method, or it won't be used anymore.
+        """
+        if not self.started:
+            raise RuntimeError("Not started")
+        if self._stores:
+            store = self._stores.pop()
+            return succeed(store)
+        elif self._stores_created < self.max_stores:
+            return self._start_store().addCallback(self._cb_get)
+        else:
+            # Maybe all stores are consumed?
+            return self.adjust_size().addCallback(self._cb_get)
+
+
+    def _cb_get(self, ign):
+        """
+        If the previous operation added a store, return it, or return a pending
+        C{Deferred}.
+        """
+        if self._stores:
+            store = self._stores.pop()
+            return store
+        else:
+            # All stores are in used, wait
+            d = Deferred()
+            self._pending_get.append(d)
+            return d
+
+
+    def put(self, store):
+        """
+        Make a store available again.
+
+        This should be done explicitely to have the store back in the pool.
+        The good way to use the pool is this:
+
+        >>> d1 = pool.get()
+
+        >>> # d1 callback with a store
+        >>> d2 = store.add(foo)
+        >>> d2.addCallback(doSomething).addErrback(manageErrors)
+        >>> d2.addBoth(lambda x: pool.put(store))
+        """
+        return store.rollback().addBoth(self._cb_put, store)
+
+
+    def _cb_put(self, passthrough, store):
+        """
+        Once the rollback has finished, the store is really available.
+        """
+        if self._pending_get:
+            # People are waiting, fire with the store
+            d = self._pending_get.pop(0)
+            d.callback(store)
+        else:
+            self._stores.append(store)
+        return passthrough
+
+
+    def transact(self, f, *args, **kwargs):
+        """
+        Call function C{f} with a L{Store} instance and arguments C{args} and
+        C{kwargs} in transaction bound to the acquired store.  If transaction
+        succeeds, store will be commited.  Store is returned to this pool after
+        call to C{f} completes.
+
+        Note that the function C{f} must return an instance of L{Deferred}.
+
+        @param f: function to call in transaction
+        @param args: positional arguments to function C{f}
+        @param kwargs: keyword arguments to function C{f}
+        """
+        return self.get(
+            ).addCallback(self._cb_transact_start, f, args, kwargs)
+
+
+    def _cb_transact_start(self, store, f, args, kwargs):
+        """
+        Call transacted function with acquired store.
+        """
+        result = maybeDeferred(f, store, *args, **kwargs)
+        result.addCallback(self._cb_transact_success, store)
+        result.addBoth(self._cb_transact_stop, store)
+        return result
+
+
+    def _cb_transact_success(self, result, store):
+        """
+        Commit and pass through function result.
+        """
+        return store.commit().addCallback(lambda ignore: result)
+
+
+    def _cb_transact_stop(self, result, store):
+        """
+        Return the store back to the pool and pass through the result again.
+        """
+        return self.put(store).addCallback(lambda ignore: result)
 
=== added file 'storm/twisted/wrapper.py'
--- storm/twisted/wrapper.py	1970-01-01 00:00:00 +0000
+++ storm/twisted/wrapper.py	2009-12-27 11:31:14 +0000
@@ -0,0 +1,206 @@
+#
+# Copyright (c) 2007 Canonical
+# Copyright (c) 2007 Thomas Herve <[e-mail]>
+#
+# This file is part of Storm Object Relational Mapper.
+#
+# Storm is free software; you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as
+# published by the Free Software Foundation; either version 2.1 of
+# the License, or (at your option) any later version.
+#
+# Storm is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+"""
+Asynchronous wrapper around storm.
+"""
+
+from storm.store import Store
+from storm.references import Reference, ReferenceSet
+
+
+try:
+    from functools import partial
+except ImportError:
+    # For Python < 2.5
+    class partial(object):
+        def __init__(self, fn, *args, **kw):
+            self.fn = fn
+            self.args = args
+            self.kw = kw
+
+        def __call__(self, *args, **kw):
+            if kw and self.kw:
+                d = self.kw.copy()
+                d.update(kw)
+            else:
+                d = kw or self.kw
+            return self.fn(*(self.args + args), **d)
+
+
+
+class DeferredResult(object):
+    """
+    Proxy for a storm result, running the blocking methods in a thread and
+    returning C{Deferred}s.
+    """
+
+    def __init__(self, thread, result):
+        """
+        @param thread: the running thread of the store
+        @type thread: C{StoreThread}
+
+        @param result: the result instance to be wrapped.
+        @type result: C{storm.database.Result}
+        """
+        self.result = result
+        for methodName in ("get_one", "get_all"):
+            method = partial(thread.defer_to_thread,
+                             getattr(result, methodName))
+            setattr(self, methodName, method)
+
+
+
+class DeferredResultSet(object):
+    """
+    Wrapper for a L{storm.store.ResultSet}.
+    """
+
+    def __init__(self, thread, resultSet):
+        """
+        Create the results with given C{StoreThread} and the set to wrap.
+        """
+        self._thread = thread
+        self._resultSet = resultSet
+        for methodName in ("any", "one", "first", "last", "remove", "count",
+                           "max", "min", "avg", "sum", "set", "is_empty"):
+            method = partial(thread.defer_to_thread,
+                             getattr(resultSet, methodName))
+            setattr(self, methodName, method)
+        for methodName in ("union", "difference", "intersection"):
+            method = partial(self._set_expr,
+                             getattr(resultSet, methodName))
+            setattr(self, methodName, method)
+        for methodName in ("order_by", "config", "group_by", "having"):
+            setattr(self, methodName, getattr(self._resultSet, methodName))
+
+
+    def all(self):
+        """
+        Specific method to emulate C{__iter__}.
+        """
+        return self._thread.defer_to_thread(list, self._resultSet)
+
+
+    def values(self, *columns):
+        """
+        Wrapper around values that remove the iterator feature to return a list
+        instead.
+        """
+        def _get_values():
+            return list(self._resultSet.values(*columns))
+        return self._thread.defer_to_thread(_get_values)
+
+
+    def _set_expr(self, method, other, all=False):
+        """
+        Wrap a set expression with a C{DeferredResultSet}.
+        """
+        return DeferredResultSet(self._thread, method(other, all))
+
+
+
+class DeferredReference(Reference):
+    """
+    A reference property but within a C{Deferred}.
+    """
+
+    def __get__(self, local, cls=None):
+        """
+        Wrapper around C{Reference.__get__}.
+        """
+        store = Store.of(local)
+        if store is None:
+            return None
+        _thread = store._deferredStore.thread
+        return _thread.defer_to_thread(Reference.__get__, self, local, cls)
+
+
+    def __set__(self, local, remote):
+        """
+        Wrapper around C{Reference.__set__}.
+        """
+        raise RuntimeError("Can't set a DeferredReference")
+
+
+
+class DeferredReferenceSet(ReferenceSet):
+    """
+    A C{ReferenceSet} but within a C{Deferred}.
+    """
+
+    def __get__(self, local, cls=None):
+        """
+        Wrapper around C{ReferenceSet.__get__}.
+        """
+        store = Store.of(local)
+        if store is None:
+            return None
+        _thread = store._deferredStore.thread
+        boundReference = ReferenceSet.__get__(self, local, cls)
+        return DeferredBoundReference(_thread, boundReference)
+
+
+
+class DeferredBoundReference(object):
+    """
+    Wrapper around C{BoundReferenceSet} and C{BoundIndirectReferenceSet}.
+    """
+
+    def __init__(self, thread, boundReference):
+        """
+        Create the reference with given C{StoreThread} and the reference to
+        wrap.
+        """
+        self._thread = thread
+        self._boundReference = boundReference
+        for methodName in ("clear", "add", "remove", "any", "count", "one",
+                           "first", "last"):
+            method = partial(thread.defer_to_thread,
+                             getattr(boundReference, methodName))
+            setattr(self, methodName, method)
+        for methodName in ("order_by", "find"):
+            method = partial(self._defer_and_wrap_result,
+                             getattr(boundReference, methodName))
+            setattr(self, methodName, method)
+
+
+    def all(self):
+        """
+        Specific method to emulate C{__iter__}.
+        """
+        return self._thread.defer_to_thread(list, self._boundReference)
+
+
+    def values(self, *columns):
+        """
+        Emulate the values method.
+        """
+        def _get_values():
+            return list(self._boundReference.values(*columns))
+        return self._thread.defer_to_thread(_get_values)
+
+
+    def _defer_and_wrap_result(self, method, *args, **kwargs):
+        """
+        Helper for methods returning another C{ResultSet}.
+        """
+        return self._thread.defer_to_thread(method, *args, **kwargs
+            ).addCallback(lambda x: DeferredResultSet(self._thread, x))
 
=== added directory 'tests/twisted'
=== added file 'tests/twisted/__init__.py'
=== added file 'tests/twisted/base.py'
--- tests/twisted/base.py	1970-01-01 00:00:00 +0000
+++ tests/twisted/base.py	2009-12-27 11:31:15 +0000
@@ -0,0 +1,1286 @@
+#
+# Copyright (c) 2007 Canonical
+# Copyright (c) 2007 Thomas Herve <[e-mail]>
+#
+# This file is part of Storm Object Relational Mapper.
+#
+# Storm is free software; you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as
+# published by the Free Software Foundation; either version 2.1 of
+# the License, or (at your option) any later version.
+#
+# Storm is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+"""
+Test for twistorm.
+"""
+
+from storm.properties import Int, Unicode
+from storm.expr import Count
+from storm.references import Reference
+from storm.exceptions import OperationalError, ThreadSafetyError
+
+from storm.twisted.store import (
+        DeferredStore, StoreThread, StorePool, AlreadyStopped )
+from storm.twisted.wrapper import DeferredReference, DeferredReferenceSet
+
+from twisted.trial.unittest import TestCase
+from twisted.internet.defer import gatherResults, deferredGenerator
+from twisted.internet.defer import waitForDeferred, DeferredList
+from twisted.internet.defer import succeed, fail
+
+
+class Foo(object):
+    """
+    Test table.
+    """
+    __storm_table__ = "foo"
+    id = Int(primary=True)
+    title = Unicode()
+
+
+
+class Bar(object):
+    """
+    Test table referencing to C{Foo}
+    """
+    __storm_table__ = "bar"
+    id = Int(primary=True)
+    title = Unicode()
+    foo_id = Int()
+    foo = DeferredReference(foo_id, Foo.id)
+
+
+
+class FooRefSet(Foo):
+    """
+    A C{Foo} class with a C{DeferredReferenceSet} to get all the bars related.
+    """
+    bars = DeferredReferenceSet(Foo.id, Bar.foo_id)
+
+
+
+class FooRefSetOrderID(Foo):
+    """
+    A C{Foo} class with an order C{DeferredReferenceSet} to C{Bar}.
+    """
+    bars = DeferredReferenceSet(Foo.id, Bar.foo_id, order_by=Bar.id)
+
+
+
+class Egg(object):
+    """
+    Test table.
+    """
+    __storm_table__ = "egg"
+    id = Int(primary=True)
+    value = Int()
+
+
+
+class DeferredStoreTest(object):
+    """
+    Tests for L{DeferredStore}.
+    """
+
+    def setUp(self):
+        """
+        Create a test sqlite database, and insert some data.
+        """
+        self.create_database()
+        connection = self.connection = self.database.connect()
+        self.drop_tables()
+        self.create_tables()
+        connection.execute("INSERT INTO foo VALUES (10, 'Title 30')")
+        connection.execute("INSERT INTO bar VALUES (10, 10, 'Title 50')")
+        connection.execute("INSERT INTO bar VALUES (11, 10, 'Title 40')")
+        connection.execute("INSERT INTO egg VALUES (1, 4)")
+        connection.execute("INSERT INTO egg VALUES (2, 3)")
+        connection.execute("INSERT INTO egg VALUES (3, 7)")
+        connection.execute("INSERT INTO egg VALUES (4, 5)")
+        connection.commit()
+        self.store = DeferredStore(self.database)
+        return self.store.start()
+
+
+    def tearDown(self):
+        """
+        Kill the store (and its underlying thread).
+        """
+        def _stop(ign):
+            return self.store.stop().addCallback(_drop)
+        def _drop(ign):
+            self.drop_tables()
+        return self.store.rollback().addCallback(_stop)
+
+
+    def create_database(self):
+        raise NotImplementedError()
+
+
+    def create_tables(self):
+        raise NotImplementedError()
+
+
+    def drop_tables(self):
+        for table in ["foo", "bar", "egg"]:
+            try:
+                self.connection.execute("DROP TABLE %s" % table)
+                self.connection.commit()
+            except:
+                self.connection.rollback()
+
+
+    def test_multiple_start(self):
+        """
+        Check that start raises an exception when the store is already started.
+        """
+        self.assertRaises(RuntimeError, self.store.start)
+
+
+    def test_get(self):
+        """
+        Try to get an object from the store and check its attributes.
+        """
+        def cb(result):
+            self.assertEquals(result.title, u"Title 30")
+            self.assertEquals(result.id, 10)
+        return self.store.get(Foo, 10).addCallback(cb)
+
+
+    def test_add(self):
+        """
+        Add an object to the store.
+        """
+        foo = Foo()
+        foo.title = u"Great title"
+        foo.id = 11
+        def cb_add(ign):
+            return self.store.get(Foo, 11).addCallback(cb_get)
+        def cb_get(result):
+            self.assertEquals(result.title, u"Great title")
+            self.assertEquals(result.id, 11)
+        return self.store.add(foo).addCallback(cb_add)
+
+
+    def test_add_default_value(self):
+        """
+        When adding an object to the store, the default values from the
+        database are retrieved and put into the object.
+        """
+        foo = Foo()
+        foo.id = 11
+        def cb_add(result):
+            self.assertIdentical(result, None)
+            return self.store.get(Foo, 11).addCallback(cb_get)
+        def cb_get(result):
+            self.assertEquals(result.title, u"Default Title")
+            self.assertEquals(result.id, 11)
+        return self.store.add(foo).addCallback(cb_add)
+
+
+    def test_execute(self):
+        """
+        Test a direct execute on the store, and the C{get_one} method of
+        C{DeferredResult}.
+        """
+        def cb_execute(result):
+            return result.get_one().addCallback(cb_result)
+        def cb_result(result):
+            self.assertEquals(result, (u"Title 30",))
+        return self.store.execute("SELECT title FROM foo WHERE id=10"
+            ).addCallback(cb_execute)
+
+
+    def test_execute_all(self):
+        """
+        Test a direct execute on the store, and the C{all} method of
+        C{DeferredResult}.
+        """
+        def cb_execute(result):
+            return result.get_all().addCallback(cb_result)
+        def cb_result(result):
+            self.assertEquals(result, [(u"Title 50",), (u"Title 40",)])
+        return self.store.execute("SELECT title FROM bar"
+            ).addCallback(cb_execute)
+
+
+    def test_remove(self):
+        """
+        Trying removing an object from the database.
+        """
+        def cb_get(result):
+            return self.store.remove(result).addCallback(cb_remove)
+        def cb_remove(ign):
+            return self.store.get(Foo, 10).addCallback(cb_get_after_remove)
+        def cb_get_after_remove(result):
+            self.assertIdentical(result, None)
+        return self.store.get(Foo, 10).addCallback(cb_get)
+
+
+    def test_find(self):
+        """
+        Try to find a list of objects using the store.
+        """
+        def cb_find(results):
+            return results.all().addCallback(cb_all)
+        def cb_all(results):
+            self.assertEquals(len(results), 2)
+            titles = [results[0].title, results[1].title]
+            titles.sort()
+            self.assertEquals(titles, [u"Title 40", u"Title 50"])
+        return self.store.find(Bar).addCallback(cb_find)
+
+
+    def test_find_first(self):
+        """
+        Try to get the first object matching a query.
+        """
+        def cb_find(results):
+            results.order_by(Bar.title)
+            return results.first().addCallback(cb_all)
+        def cb_all(result):
+            self.assertEquals(result.title, u"Title 40")
+            self.assertEquals(result.id, 11)
+        return self.store.find(Bar).addCallback(cb_find)
+
+
+    def test_find_last(self):
+        """
+        Try to get the last object matching a query.
+        """
+        def cb_find(results):
+            results.order_by(Bar.title)
+            return results.last().addCallback(cb_all)
+        def cb_all(result):
+            self.assertEquals(result.title, u"Title 50")
+            self.assertEquals(result.id, 10)
+        return self.store.find(Bar).addCallback(cb_find)
+
+
+    def test_find_any(self):
+        """
+        Try to get an object matching a query using the C{any} method.
+        """
+        def cb_find(results):
+            return results.any().addCallback(cb_all)
+        def cb_all(result):
+            self.assertEquals(result.title, u"Title 50")
+            self.assertEquals(result.id, 10)
+        return self.store.find(Bar).addCallback(cb_find)
+
+
+    def test_find_max(self):
+        """
+        Try to get the maximum of a value after a find.
+        """
+        def cb_find(results):
+            return results.max(Egg.value).addCallback(cb_all)
+        def cb_all(result):
+            self.assertEquals(result, 7)
+        return self.store.find(Egg).addCallback(cb_find)
+
+
+    def test_find_min(self):
+        """
+        Try to get the minimum of a value after a find.
+        """
+        def cb_find(results):
+            return results.min(Egg.value).addCallback(cb_all)
+        def cb_all(result):
+            self.assertEquals(result, 3)
+        return self.store.find(Egg).addCallback(cb_find)
+
+
+    def test_find_avg(self):
+        """
+        Try to get the average of a value after a find.
+        """
+        def cb_find(results):
+            return results.avg(Egg.value).addCallback(cb_all)
+        def cb_all(result):
+            self.assertEquals(result, 4.75)
+        return self.store.find(Egg).addCallback(cb_find)
+
+
+    def test_find_sum(self):
+        """
+        Try to get the sum of a value after a find.
+        """
+        def cb_find(results):
+            return results.sum(Egg.value).addCallback(cb_all)
+        def cb_all(result):
+            self.assertEquals(result, 19)
+        return self.store.find(Egg).addCallback(cb_find)
+
+
+    def test_find_count(self):
+        """
+        Try to get the count of a result after a find.
+        """
+        def cb_find(results):
+            return results.count().addCallback(cb_all)
+        def cb_all(result):
+            self.assertEquals(result, 2)
+        return self.store.find(Egg, Egg.value >= 5).addCallback(cb_find)
+
+
+    def test_find_remove(self):
+        """
+        Remove the result of a find query.
+        """
+        def cb_find(results):
+            return results.remove().addCallback(cb_remove)
+        def cb_remove(ignore):
+            return self.store.find(Egg).addCallback(cb_find_after_remove)
+        def cb_find_after_remove(results):
+            return results.all().addCallback(cb_all)
+        def cb_all(results):
+            self.assertEquals(len(results), 2)
+        return self.store.find(Egg, Egg.value >= 5).addCallback(cb_find)
+
+
+    def test_find_limit(self):
+        """
+        Put a limit on the number of results of a find.
+        """
+        def cb_find(results):
+            results.config(limit=3)
+            return results.all().addCallback(cb_all)
+        def cb_all(results):
+            self.assertEquals(len(results), 3)
+        return self.store.find(Egg).addCallback(cb_find)
+
+
+    def test_find_union(self):
+        """
+        Call C{union} on 2 differents C{DeferredResultSet}.
+        """
+        def cb_find(results):
+            result1, result2 = results
+            results = result1.union(result2._resultSet)
+            return results.all().addCallback(cb_all)
+        def cb_all(results):
+            self.assertEquals(len(results), 3)
+        d1 = self.store.find(Egg, Egg.value >= 5)
+        d2 = self.store.find(Egg, Egg.value == 3)
+        return gatherResults([d1, d2]).addCallback(cb_find)
+
+
+    def test_find_difference(self):
+        """
+        Call C{union} on 2 differents C{DeferredResultSet}.
+        """
+        if self.__class__.__name__.startswith("MySQL"):
+            return
+        def cb_find(results):
+            result1, result2 = results
+            results = result1.difference(result2._resultSet)
+            return results.all().addCallback(cb_all)
+        def cb_all(results):
+            self.assertEquals(len(results), 1)
+            self.assertEquals(results[0].value, 5)
+        d1 = self.store.find(Egg, Egg.value >= 5)
+        d2 = self.store.find(Egg, Egg.value == 7)
+        return gatherResults([d1, d2]).addCallback(cb_find)
+
+
+    def test_find_intersection(self):
+        """
+        Call C{intersection} on 2 differents C{DeferredResultSet}.
+        """
+        if self.__class__.__name__.startswith("MySQL"):
+            return
+        def cb_find(results):
+            result1, result2 = results
+            results = result1.intersection(result2._resultSet)
+            return results.all().addCallback(cb_all)
+        def cb_all(results):
+            self.assertEquals(len(results), 1)
+            self.assertEquals(results[0].value, 7)
+        d1 = self.store.find(Egg, Egg.value >= 5)
+        d2 = self.store.find(Egg, Egg.value == 7)
+        return gatherResults([d1, d2]).addCallback(cb_find)
+
+
+    def test_find_values(self):
+        """
+        Filter the fields returned by a find using the values method.
+        """
+        def cb_find(results):
+            return results.values(Bar.title).addCallback(cb_all)
+        def cb_all(titles):
+            titles.sort()
+            self.assertEquals(titles, [u"Title 40", u"Title 50"])
+        return self.store.find(Bar).addCallback(cb_find)
+
+
+    def test_find_and_set(self):
+        """
+        The C{set} method of a C{ResultSet} should update the specified fields
+        in a thread.
+        """
+        def cb_find(results):
+            return results.set(title=u"Title").addCallback(cb_set, results)
+        def cb_set(ignore, results):
+            return results.values(Bar.title).addCallback(cb_all)
+        def cb_all(titles):
+            titles.sort()
+            self.assertEquals(titles, [u"Title", u"Title"])
+        return self.store.find(Bar).addCallback(cb_find)
+
+
+    def test_find_offset(self):
+        """
+        Put an offset on the number of results of a find.
+        """
+        def cb_find(results):
+            results.config(offset=2)
+            return results.all().addCallback(cb_all)
+        def cb_all(results):
+            self.assertEquals(len(results), 2)
+        return self.store.find(Egg).addCallback(cb_find)
+
+
+    def test_find_offset_limit(self):
+        """
+        Put an offset and limit in the number of results of a find.
+        """
+        def cb_find(results):
+            results.config(offset=1, limit=2)
+            return results.all().addCallback(cb_all)
+        def cb_all(results):
+            self.assertEquals(len(results), 2)
+        return self.store.find(Egg).addCallback(cb_find)
+
+
+    @deferredGenerator
+    def test_find_defgen(self):
+        """
+        Do a find, add an object, then do another find: this to ensure that the
+        connection remains in the dedicated thread.
+        """
+        d = self.store.find(Bar)
+        wfd = waitForDeferred(d)
+        yield wfd
+        results = wfd.getResult()
+        d =  results.all()
+        wfd = waitForDeferred(d)
+        yield wfd
+        wfd.getResult()
+        foo = Foo()
+        foo.title = u"Great title"
+        foo.id = 11
+        d = self.store.add(foo)
+        wfd = waitForDeferred(d)
+        yield wfd
+        wfd.getResult()
+        d = self.store.find(Foo)
+        wfd = waitForDeferred(d)
+        yield wfd
+        results = wfd.getResult()
+
+
+    def test_find_order_by(self):
+        """
+        Try to find a list of objects using the store, then order the result
+        set.
+        """
+        def cb_find(results):
+            results.order_by(Bar.title)
+            return results.all().addCallback(cb_all)
+        def cb_all(results):
+            self.assertEquals(len(results), 2)
+            titles = [results[0].title, results[1].title]
+            self.assertEquals(titles, [u"Title 40", u"Title 50"])
+        return self.store.find(Bar).addCallback(cb_find)
+
+
+    def test_find_and_rollback(self):
+        """
+        Accessing an object outside of a transaction fails because the object
+        hasn't been resolved yet.
+        """
+        def cb_find(results):
+            results.order_by(Bar.title)
+            return results.all().addCallback(cb_all)
+        def cb_all(results):
+            return self.store.rollback().addCallback(cbRollback, results)
+        def cbRollback(ign, results):
+            self.assertEquals(len(results), 2)
+            self.assertRaises(RuntimeError, getattr, results[0], "title")
+        return self.store.find(Bar).addCallback(cb_find)
+
+
+    def test_find_is_empty(self):
+        """
+        DeferredReference.is_empty returns a Deferred that fires with True or
+        False depending if the matched result set is empty or not.
+        """
+        def cb_find(results):
+            return results.is_empty().addCallback(self.assertEquals, False)
+
+        return self.store.find(Bar).addCallback(cb_find)
+
+
+    def test_find_group_by(self):
+        """
+        DeferredReference.group_by is a simple wrapper to the group_by method
+        of the reference set.
+        """
+        def cb_find(results):
+            results.group_by(Bar.foo_id)
+            return results.all().addCallback(check)
+
+        def check(result):
+            self.assertEquals(result, [(2, 10)])
+
+        return self.store.find((Count(Bar.id), Bar.foo_id)
+            ).addCallback(cb_find)
+
+
+    def test_find_having(self):
+        """
+        DeferredReference.having is a simple wrapper to the having method of
+        the reference set.
+        """
+        connection = self.database.connect()
+        connection.execute("INSERT INTO egg VALUES (5, 7)")
+        connection.commit()
+
+        def cb_find(results):
+            results.group_by(Egg.value)
+            results.having(Egg.value >= 5)
+            results.order_by(Egg.value)
+            return results.all().addCallback(check)
+
+        def check(result):
+            self.assertEquals(result, [(1, 5), (2, 7)])
+
+        return self.store.find((Count(Egg.id), Egg.value)
+            ).addCallback(cb_find)
+
+
+    def test_reference(self):
+        """
+        Trying to get a reference of an object using C{DeferredReference}.
+        """
+        def cb_getBar(result):
+            return result.foo.addCallback(cb_getFoo)
+        def cb_getFoo(fooResult):
+            return self.store.get(Foo, 10).addCallback(cb_getFooBar, fooResult)
+        def cb_getFooBar(result, fooResult):
+            self.assertIdentical(fooResult, result)
+            # The result should be valid too
+            self.assertEquals(fooResult.title, u"Title 30")
+        return self.store.get(Bar, 10).addCallback(cb_getBar)
+
+
+    def test_reference_setting(self):
+        """
+        Try to set a reference of an object.
+        """
+        connection = self.database.connect()
+        connection.execute("INSERT INTO foo VALUES (20, 'Title 20')")
+        connection.commit()
+        def cb_getBar(result):
+            return self.store.get(Foo, 20).addCallback(cb_getFooBar, result)
+        def cb_getFooBar(result, barResult):
+            self.assertRaises(RuntimeError, setattr, barResult, "foo", result)
+        return self.store.get(Bar, 10).addCallback(cb_getBar)
+
+
+    def test_reference_set_unordered(self):
+        """
+        Get a reference set and call various wrapped methods on it.
+        """
+        # find test
+        def cb_find(results):
+            return results.all().addCallback(cb_all)
+
+        def cb_all(results):
+            self.assertEquals(len(results), 2)
+            titles = [results[0].title, results[1].title]
+            titles.sort()
+            self.assertEquals(titles, [u"Title 40", u"Title 50"])
+
+        def cb_any(result):
+            self.assertTrue(result)
+
+        def cb_values(titles):
+            titles.sort()
+            self.assertEquals(titles, [u"Title 40", u"Title 50"])
+
+        def do_tests(results):
+            results = results.bars
+            dfrs = [
+                results.find().addCallback(cb_find),
+                results.any().addCallback(cb_any),
+                results.values(Bar.title).addCallback(cb_values),
+            ]
+            return DeferredList(dfrs)
+
+        return self.store.get(FooRefSet, 10).addCallback(do_tests)
+
+
+    def test_reference_set_ordered(self):
+        """
+        A DeferredReferenceSet has a order_by method which returns a Deferred
+        firing when the reference set is ordered.
+        """
+        def do_tests(result):
+            dfrs = [
+                result.first().addCallback(lambda t:
+                        self.assertEquals(t.title, u"Title 40")),
+                result.last().addCallback(lambda t:
+                        self.assertEquals(t.title, u"Title 50")),
+                    ]
+            return DeferredList(dfrs)
+
+        def order(results):
+            dfr = results.bars.order_by("title")
+            return dfr.addCallback(do_tests)
+
+        return self.store.get(FooRefSet, 10).addCallback(order)
+
+
+    def test_reference_set_add_remove(self):
+        """
+        A DeferredReferenceSet has a add method with returns a Deferred once
+        the object has been added.
+        Try to add things from the reference set async.
+        """
+        def add_one(result):
+            bar = Bar()
+            bar.title = u"Yeah"
+            return result.bars.add(bar).addCallback(remove_one, result, bar)
+
+        def remove_one(add_result, result, bar):
+            return result.bars.remove(bar).addCallback(get_all, result)
+
+        def get_all(ignore, result):
+            return result.bars.all().addCallback(check)
+
+        def check(result):
+            self.assertEquals(len(result), 2)
+
+        return self.store.get(FooRefSet, 10).addCallback(add_one)
+
+
+    def test_reference_set_clear(self):
+        """
+        A DeferredReferenceSet has a clear method which removes all elements
+        from the reference set and fires the returned Deferred when done.
+        """
+        def first_cb(result):
+            refs = result.bars
+            return check_count(refs, 2).addCallback(clear_cb, refs)
+
+        def check_count(ref_set, num):
+            return ref_set.count().addCallback(self.assertEquals, num)
+
+        def clear_cb(result, refs):
+            return refs.clear().addCallback(lambda x: check_count(refs, 0))
+
+        return self.store.get(FooRefSet, 10).addCallback(first_cb)
+
+
+    def test_reference_set_one(self):
+        """
+        Call C{one} on a C{DeferredBoundReference}.
+        """
+        connection = self.database.connect()
+        connection.execute("INSERT INTO foo VALUES (11, 'Title 40')")
+        connection.execute("INSERT INTO bar VALUES (20, 11, 'Title 50')")
+        connection.commit()
+        def cb_get(result):
+            return result.bars.one().addCallback(cb_one)
+        def cb_one(result):
+            return self.store.get(Bar, 20).addCallback(check, result)
+        def check(result, expected):
+            self.assertIdentical(result, expected)
+        return self.store.get(FooRefSet, 11).addCallback(cb_get)
+
+
+    def test_reference_set_first(self):
+        """
+        Call C{first} on an ordered C{DeferredBoundReference}.
+        """
+        def cb_get(result):
+            return result.bars.first().addCallback(cb_one)
+        def cb_one(result):
+            return self.store.get(Bar, 10).addCallback(check, result)
+        def check(result, expected):
+            self.assertIdentical(result, expected)
+        return self.store.get(FooRefSetOrderID, 10).addCallback(cb_get)
+
+
+    def test_reference_set_last(self):
+        """
+        Call C{last} on an ordered C{DeferredBoundReference}.
+        """
+        def cb_get(result):
+            return result.bars.last().addCallback(cb_one)
+        def cb_one(result):
+            return self.store.get(Bar, 11).addCallback(check, result)
+        def check(result, expected):
+            self.assertIdentical(result, expected)
+        return self.store.get(FooRefSetOrderID, 10).addCallback(cb_get)
+
+
+    def test_commit(self):
+        """
+        Make some changes and commit them.
+        """
+        def cb_get(result):
+            return self.store.remove(result).addCallback(cb_remove)
+        def cb_remove(ign):
+            return self.store.commit().addCallback(cb_commit)
+        def cb_commit(ign):
+            # To be sure the data is no more in the db, the best is to
+            # directly connect to the db
+            connection = self.database.connect()
+            result = connection.execute("SELECT * FROM foo")
+            self.assertEquals(list(result), [])
+        return self.store.get(Foo, 10).addCallback(cb_get)
+
+
+    def test_rollback(self):
+        """
+        Make and some changes and rollback them.
+        """
+        def cb_get(result):
+            return self.store.remove(result).addCallback(cb_remove)
+        def cb_remove(ign):
+            return self.store.rollback().addCallback(cbRollback)
+        def cbRollback(ign):
+            connection = self.database.connect()
+            result = connection.execute("SELECT * FROM foo")
+            self.assertEquals(list(result), [(10, u"Title 30")])
+        return self.store.get(Foo, 10).addCallback(cb_get)
+
+
+    def test_deferred_reference_multithread(self):
+        """
+        If a store is restarted, the objects in the cache should still be
+        usable, in particular an object shouldn't not store a reference to the
+        store thread, as it can change.
+        """
+        def test(ignore):
+            # get a bar and retrieve the deferred reference
+            def get_foo(bar):
+                return bar.foo
+
+            return self.store.find(Bar, Bar.id == 10).addCallback(lambda x:
+                    x.one()).addCallback(get_foo)
+
+        def _restart_store(res):
+            def stopped(res):
+                self.store = DeferredStore(self.database)
+                return self.store.start()
+            return self.store.stop().addCallback(stopped)
+
+        def check(foo):
+            self.assertEquals(foo.id, 10)
+            self.assertEquals(foo.title, u"Title 30")
+
+        return test(None
+            ).addCallback(_restart_store
+            ).addCallback(test
+            ).addCallback(check)
+
+
+    def test_of(self):
+        """
+        The DeferredStore associated with an object is returned by the static
+        C{of} method.
+        """
+        def cb_get(result):
+            store = DeferredStore.of(result)
+            self.assertIdentical(self.store, store)
+
+        return self.store.get(Foo, 10).addCallback(cb_get)
+
+
+    def test_thread_check(self):
+        """
+        A L{ThreadSafetyError} is raised when attempting to do an unsafe
+        operation, like accessing a C{Reference} attribute via a
+        C{DeferredStore}.
+        """
+        class WrongBar(Bar):
+            foo_sync = Reference(Bar.foo_id, Foo.id)
+        d = self.store.find(WrongBar).addCallback(lambda result: result.all())
+
+        def check(results):
+            self.assertRaises(
+                ThreadSafetyError, getattr, results[0], "foo_sync")
+        return d.addCallback(check)
+
+
+
+class StoreThreadTestCase(TestCase):
+    """
+    Tests for L{StoreThread}.
+    """
+
+    def setUp(self):
+        """
+        Create an instance of C{StoreThread} and start it.
+        """
+        self.thread = StoreThread()
+        self.thread.start()
+
+
+    def tearDown(self):
+        """
+        Kill the running thread.
+        """
+        self.thread.stop()
+
+
+    def test_defer_after_stop(self):
+        """
+        Deferring calls after store is stopped raises C{AlreadyStopped}.
+        """
+        def cb_stop(r):
+            self.assertFailure(self.thread.defer_to_thread(lambda f : None),
+                    AlreadyStopped)
+        return self.thread.stop().addCallback(cb_stop)
+
+
+    def test_callback(self):
+        """
+        Fire a simple function in a thread and check its result.
+        """
+        def testfunc():
+            return 1
+        return self.thread.defer_to_thread(testfunc
+            ).addCallback(self.assertEquals, 1)
+
+
+    def test_errback(self):
+        """
+        Raising an exception in a thread returns a failure.
+        """
+        def testfunc():
+            raise RuntimeError("Error!")
+        return self.assertFailure(self.thread.defer_to_thread(testfunc),
+                                  RuntimeError)
+
+
+
+class StorePoolTest(object):
+    """
+    Tests for L{StorePool}.
+    """
+
+    def setUp(self):
+        """
+        Build a database with data, a create a pool.
+        """
+        self.create_database()
+        connection = self.connection = self.database.connect()
+        self.drop_tables()
+        self.create_tables()
+        connection.execute("INSERT INTO foo VALUES (10, 'Title 30')")
+        connection.execute("INSERT INTO bar VALUES (10, 10, 'Title 40')")
+        connection.execute("INSERT INTO bar VALUES (11, 10, 'Title 50')")
+        connection.commit()
+        self.pool = StorePool(self.database, 2, 5)
+        return self.pool.start()
+
+
+    def tearDown(self):
+        """
+        Stop the pool.
+        """
+        def _drop(ign):
+            self.drop_tables()
+        return self.pool.stop().addCallback(_drop)
+
+
+    def drop_tables(self):
+        for table in ["foo", "bar"]:
+            try:
+                self.connection.execute("DROP TABLE %s" % table)
+                self.connection.commit()
+            except:
+                self.connection.rollback()
+
+
+    def test_already_started(self):
+        """
+        Check that the pool can't be restarted multiple times.
+        """
+        self.assertRaises(RuntimeError, self.pool.start)
+
+
+    def test_get(self):
+        """
+        get should return different stores if available.
+        """
+        def cb_get1(store1):
+            return self.pool.get().addCallback(cb_get2, store1)
+        def cb_get2(store2, store1):
+            self.assertNotIdentical(store1, store2)
+            self.assertTrue(store1.started)
+            self.assertTrue(store2.started)
+        return self.pool.get().addCallback(cb_get1)
+
+
+    def test_get_not_started(self):
+        """
+        If no store are available, the pool should create a store.
+        """
+        def cb(ign):
+            self.assertEquals(self.pool._stores_created, 0)
+            return self.pool.adjust_size(0, 5).addCallback(cb_add)
+        def cb_add(ign):
+            return self.pool.get().addCallback(cb_get)
+        def cb_get(store):
+            self.assertTrue(store.started)
+        return self.pool.adjust_size(0, 0).addCallback(cb)
+
+
+    def test_waiting_for_store(self):
+        """
+        Test waiting for a store availability.
+        """
+        def cb(ign):
+            return self.pool.get().addCallback(cb_get1)
+        def cb_get1(store1):
+            self.assertTrue(store1.started)
+            # Now we have a store, no store should be returned by the pool
+            # until we put it back
+            d1 = self.pool.get().addCallback(cb_get2, store1)
+            d2 = self.pool.put(store1)
+            return gatherResults([d1, d2])
+        def cb_get2(store2, store1):
+            self.assertIdentical(store1, store2)
+        return self.pool.adjust_size(1, 1).addCallback(cb)
+
+
+    def test_adjust_size_minmax(self):
+        """
+        Test sanity check on min/max - i.e. min <= max.
+        """
+        return self.assertFailure(self.pool.adjust_size(2, 1), ValueError)
+
+
+    def test_adjust_size_nonnegative(self):
+        """
+        Test sanity check for nonnegative min.
+        """
+        return self.assertFailure(self.pool.adjust_size(-1), ValueError)
+
+
+    @deferredGenerator
+    def test_concurrent_data(self):
+        """
+        Test that different stores have different states: if the first store
+        hasn't yet committed, the second one shouldn't get the new data.
+        """
+        foo = Foo()
+        foo.title = u"Great title"
+        foo.id = 11
+        d = self.pool.get()
+        wfd = waitForDeferred(d)
+        yield wfd
+        store1 = wfd.getResult()
+
+        d = self.pool.get()
+        wfd = waitForDeferred(d)
+        yield wfd
+        store2 = wfd.getResult()
+
+        d = store1.add(foo)
+        wfd = waitForDeferred(d)
+        yield wfd
+        wfd.getResult()
+
+        d = store1.get(Foo, 11)
+        wfd = waitForDeferred(d)
+        yield wfd
+        foo2 = wfd.getResult()
+
+        # The object is already in the store cache
+        self.assertIdentical(foo2, foo)
+
+        d = store2.get(Foo, 11)
+        wfd = waitForDeferred(d)
+        yield wfd
+        foo3 = wfd.getResult()
+
+        # The object isn't in the db yet
+        self.assertIdentical(foo3, None)
+
+        # Let's rollback, because even select open a transaction
+        d = store2.rollback()
+        wfd = waitForDeferred(d)
+        yield wfd
+        wfd.getResult()
+
+        # Let's commit
+        d = store1.commit()
+        wfd = waitForDeferred(d)
+        yield wfd
+        wfd.getResult()
+
+        d = store2.get(Foo, 11)
+        wfd = waitForDeferred(d)
+        yield wfd
+        foo4 = wfd.getResult()
+
+        # The objects must be different
+        self.assertNotIdentical(foo4, foo)
+        # But the content must be the same
+        self.assertEquals(foo4.title, u"Great title")
+
+
+    def test_no_overflow(self):
+        """
+        Test that pool does not allocate more connections than store_max.
+        """
+        ds = []
+        stores = set()
+
+        def cb_get(store):
+            stores.add(store)
+            return self.pool.put(store)
+
+        for i in range(10):
+            ds.append(self.pool.get().addCallback(cb_get))
+
+        def checkInstances(result):
+            self.assertEquals(len(stores), 5)
+
+        return gatherResults(ds).addCallback(checkInstances)
+
+
+    def test_start_failure(self):
+        """
+        If a store failed to start, the number of allocated connections doesn't
+        grow, so we're later able to start more stores.
+        """
+        ds = []
+        stores = set()
+
+        class DontStartStore(DeferredStore):
+            def start(self):
+                return fail(RuntimeError("oops"))
+
+        calls = []
+
+        def vicious_store_factory(database):
+            if not calls:
+                store = DontStartStore(database)
+            else:
+                store = DeferredStore(database)
+            calls.append(None)
+            return store
+
+        self.pool.store_factory = vicious_store_factory
+
+        def cb_get(store):
+            stores.add(store)
+            return self.pool.put(store)
+
+        errors = []
+
+        def save_errors(failure):
+            errors.append(failure)
+
+        for i in range(6):
+            ds.append(
+                self.pool.get().addCallback(cb_get).addErrback(save_errors))
+
+        def checkInstances(result):
+            self.assertEquals(len(stores), 5)
+            self.assertEquals(len(errors), 1)
+            errors[0].trap(RuntimeError)
+
+        return gatherResults(ds).addCallback(checkInstances)
+
+
+    def test_arguments(self):
+        """
+        Arguments are passed along to transacted method when store
+        is available.
+        """
+        def tx(store, a, b=None):
+            self.assertIsInstance(store, DeferredStore)
+            self.assertEquals(1, a)
+            self.assertEquals(2, b)
+            return succeed("ok")
+        return self.pool.transact(tx, 1, b=2)
+
+
+    def test_commit(self):
+        """
+        Changes made inside a successful transaction are committed.
+        """
+        @deferredGenerator
+        def check(result):
+            d = self.pool.get()
+            wfd = waitForDeferred(d)
+            yield wfd
+            store = wfd.getResult()
+            d = store.execute("SELECT * FROM foo ORDER BY id", [])
+            wfd = waitForDeferred(d)
+            yield wfd
+            dr = wfd.getResult()
+            d = dr.get_all()
+            wfd = waitForDeferred(d)
+            yield wfd
+            results = wfd.getResult()
+            self.assertEquals(2, len(results))
+            self.assertEquals(1, results[0][0])
+            self.assertEquals("test", results[0][1])
+
+        def tx(store):
+            d = store.execute("INSERT INTO foo(id, title) "
+                              "VALUES (1, 'test')", noresult=True)
+            return d
+
+        return self.pool.transact(tx).addCallback(check)
+
+
+    def test_rollback(self):
+        """
+        Changes made inside a failed transaction are rolled back.
+        """
+        @deferredGenerator
+        def check(reason):
+            d = self.pool.get()
+            wfd = waitForDeferred(d)
+            yield wfd
+            store = wfd.getResult()
+            d = store.execute("SELECT * FROM foo", [])
+            wfd = waitForDeferred(d)
+            yield wfd
+            dr = wfd.getResult()
+            d = dr.get_all()
+            wfd = waitForDeferred(d)
+            yield wfd
+            results = wfd.getResult()
+            self.assertEquals(1, len(results))
+
+        @deferredGenerator
+        def tx(store):
+            d = store.execute("INSERT INTO foo(id, title) "
+                              "VALUES (1, 'test')", [])
+            wfd = waitForDeferred(d)
+            yield wfd
+            wfd.getResult()
+            d = store.execute("INSERT INTO foo(id, title) "
+                              "VALUES (1, 'test')", [])
+            wfd = waitForDeferred(d)
+            yield wfd
+            wfd.getResult()
+
+        return self.pool.transact(tx).addBoth(check)
+
+
+    def test_return_value(self):
+        """
+        Final return value should match return value from successful call to
+        transacted function.
+        """
+        def check(result):
+            self.assertEquals("completed", result)
+
+        def cb(result):
+            return "completed"
+
+        def tx(store):
+            return store.execute("INSERT INTO foo(id, title) "
+                                 "VALUES (1, 'test')", []
+                    ).addCallback(cb)
+
+        return self.pool.transact(tx).addCallback(check)
+
+
+    def test_poolsize_after_success(self):
+        """
+        After successful transaction, pool size should be same size as before.
+        """
+        size = len(self.pool._stores)
+
+        def check(result):
+            self.assertEquals(size, len(self.pool._stores))
+
+        def tx(store):
+            d = store.execute("SELECT * from foo", [])
+            return d.addCallback(lambda result: result.get_all())
+
+        return self.pool.transact(tx).addCallback(check)
+
+
+    def test_poolsize_after_failure(self):
+        """
+        After failed transaction, pool size is restored to the initial value.
+        """
+        size = len(self.pool._stores)
+
+        def check(reason):
+            self.assertEquals(size, len(self.pool._stores))
+
+        def tx(store):
+            return store.execute("SELECT * from not_a_table", [])
+
+        d = self.assertFailure(self.pool.transact(tx), OperationalError)
+        return d.addCallback(check)
+
+
+    def test_failure_propagation(self):
+        """
+        A custom exception is propagated by a C{transact} call.
+        """
+        class MyException(Exception):
+            pass
+
+        def tx(store):
+            raise MyException("Bad things happened")
+
+        return self.assertFailure(self.pool.transact(tx), MyException)
+
+
+    def test_non_deferred_function(self):
+        """
+        C{transact} can handle functions that don't return a C{Deferred}.
+        """
+        def tx(store):
+            return "foo"
+        return self.pool.transact(tx).addCallback(self.assertEquals, "foo")
+
+
+    def test_rollback_failure(self):
+        """
+        If C{rollback} fails, the store is put back into the pool.
+        """
+
+        def cb_get(store):
+            store.rollback = lambda: fail(RuntimeError("oops"))
+            d = self.assertFailure(self.pool.put(store), RuntimeError)
+            return d.addCallback(get_all)
+
+        def get_all(ignore):
+            dl = []
+            for i in range(5):
+                dl.append(self.pool.get())
+            return gatherResults(dl).addCallback(check)
+
+        def check(stores):
+            # The fact that we're here show that the test succeeds, because we
+            # didn't hang waiting for a store
+            self.assertEquals(len(stores), 5)
+
+        return self.pool.get().addCallback(cb_get)
 
=== added file 'tests/twisted/mysql.py'
--- tests/twisted/mysql.py	1970-01-01 00:00:00 +0000
+++ tests/twisted/mysql.py	2009-12-27 11:31:15 +0000
@@ -0,0 +1,62 @@
+import os
+
+from storm.database import create_database
+
+from tests.twisted.base import DeferredStoreTest, StorePoolTest
+
+from twisted.trial.unittest import TestCase
+
+
+class MySQLDeferredStoreTest(TestCase, DeferredStoreTest):
+
+    def setUp(self):
+        return DeferredStoreTest.setUp(self)
+
+    def tearDown(self):
+        return DeferredStoreTest.tearDown(self)
+
+    def is_supported(self):
+        return bool(os.environ.get("STORM_MYSQL_URI"))
+
+    def create_database(self):
+        self.database = create_database(os.environ["STORM_MYSQL_URI"])
+
+    def create_tables(self):
+        connection = self.connection
+        connection.execute("CREATE TABLE foo "
+                           "(id INT PRIMARY KEY AUTO_INCREMENT,"
+                           " title VARCHAR(50) DEFAULT 'Default Title')"
+                           " ENGINE=InnoDB")
+        connection.execute("CREATE TABLE bar "
+                           "(id INT PRIMARY KEY AUTO_INCREMENT,"
+                           " foo_id INTEGER, title VARCHAR(50))"
+                           " ENGINE=InnoDB")
+        connection.execute("CREATE TABLE egg "
+                           "(id INT PRIMARY KEY AUTO_INCREMENT, value INTEGER)"
+                           " ENGINE=InnoDB")
+
+
+class MySQLStorePoolTest(TestCase, StorePoolTest):
+
+    def setUp(self):
+        return StorePoolTest.setUp(self)
+
+    def tearDown(self):
+        return StorePoolTest.tearDown(self)
+
+    def is_supported(self):
+        return bool(os.environ.get("STORM_MYSQL_URI"))
+
+    def create_database(self):
+        self.database = create_database(os.environ["STORM_MYSQL_URI"])
+
+    def create_tables(self):
+        connection = self.connection
+        connection.execute("CREATE TABLE foo "
+                           "(id INT PRIMARY KEY AUTO_INCREMENT,"
+                           " title VARCHAR(50) DEFAULT 'Default Title')"
+                           " ENGINE=InnoDB")
+        connection.execute("CREATE TABLE bar "
+                           "(id INT PRIMARY KEY AUTO_INCREMENT,"
+                           " foo_id INTEGER, title VARCHAR(50))"
+                           " ENGINE=InnoDB")
 
=== added file 'tests/twisted/postgres.py'
--- tests/twisted/postgres.py	1970-01-01 00:00:00 +0000
+++ tests/twisted/postgres.py	2009-12-27 11:31:15 +0000
@@ -0,0 +1,57 @@
+import os
+
+from storm.database import create_database
+
+from tests.twisted.base import DeferredStoreTest, StorePoolTest
+
+from twisted.trial.unittest import TestCase
+
+
+class PostgresDeferredStoreTest(TestCase, DeferredStoreTest):
+
+    def setUp(self):
+        return DeferredStoreTest.setUp(self)
+
+    def tearDown(self):
+        return DeferredStoreTest.tearDown(self)
+
+    def is_supported(self):
+        return bool(os.environ.get("STORM_POSTGRES_URI"))
+
+    def create_database(self):
+        self.database = create_database(os.environ["STORM_POSTGRES_URI"])
+
+    def create_tables(self):
+        connection = self.connection
+        connection.execute("CREATE TABLE foo "
+                           "(id SERIAL PRIMARY KEY,"
+                           " title VARCHAR DEFAULT 'Default Title')")
+        connection.execute("CREATE TABLE bar "
+                           "(id SERIAL PRIMARY KEY,"
+                           " foo_id INTEGER, title VARCHAR)")
+        connection.execute("CREATE TABLE egg "
+                           "(id SERIAL PRIMARY KEY, value INTEGER)")
+
+
+class PostgresStorePoolTest(TestCase, StorePoolTest):
+
+    def setUp(self):
+        return StorePoolTest.setUp(self)
+
+    def tearDown(self):
+        return StorePoolTest.tearDown(self)
+
+    def is_supported(self):
+        return bool(os.environ.get("STORM_POSTGRES_URI"))
+
+    def create_database(self):
+        self.database = create_database(os.environ["STORM_POSTGRES_URI"])
+
+    def create_tables(self):
+        connection = self.connection
+        connection.execute("CREATE TABLE foo "
+                           "(id SERIAL PRIMARY KEY,"
+                           " title VARCHAR DEFAULT 'Default Title')")
+        connection.execute("CREATE TABLE bar "
+                           "(id SERIAL PRIMARY KEY,"
+                           " foo_id INTEGER, title VARCHAR)")
 
=== added file 'tests/twisted/sqlite.py'
--- tests/twisted/sqlite.py	1970-01-01 00:00:00 +0000
+++ tests/twisted/sqlite.py	2009-12-27 11:31:15 +0000
@@ -0,0 +1,65 @@
+from storm.databases.sqlite import SQLite
+from storm.uri import URI
+
+from tests.twisted.base import DeferredStoreTest, StorePoolTest
+from tests.helper import TestHelper, MakePath
+
+from twisted.trial.unittest import TestCase
+
+
+class SQLiteDeferredStoreTest(TestCase, TestHelper, DeferredStoreTest):
+
+    helpers = [MakePath]
+
+    def setUp(self):
+        TestHelper.setUp(self)
+        return DeferredStoreTest.setUp(self)
+
+    def tearDown(self):
+        def cb(passthrough):
+            TestHelper.tearDown(self)
+            return passthrough
+        return DeferredStoreTest.tearDown(self).addBoth(cb)
+
+    def create_database(self):
+        self.database = SQLite(URI("sqlite:%s?synchronous=OFF" %
+                                   self.make_path()))
+
+    def create_tables(self):
+        connection = self.connection
+        connection.execute("CREATE TABLE foo "
+                           "(id INTEGER PRIMARY KEY,"
+                           " title VARCHAR DEFAULT 'Default Title')")
+        connection.execute("CREATE TABLE bar "
+                           "(id INTEGER PRIMARY KEY,"
+                           " foo_id INTEGER, title VARCHAR)")
+        connection.execute("CREATE TABLE egg "
+                           "(id INTEGER PRIMARY KEY, value INTEGER)")
+
+
+class SQLiteStorePoolTest(TestCase, TestHelper, StorePoolTest):
+
+    helpers = [MakePath]
+
+    def setUp(self):
+        TestHelper.setUp(self)
+        return StorePoolTest.setUp(self)
+
+    def tearDown(self):
+        def cb(passthrough):
+            TestHelper.tearDown(self)
+            return passthrough
+        return StorePoolTest.tearDown(self).addBoth(cb)
+
+    def create_database(self):
+        self.database = SQLite(URI("sqlite:%s?synchronous=OFF" %
+                                   self.make_path()))
+
+    def create_tables(self):
+        connection = self.connection
+        connection.execute("CREATE TABLE foo "
+                           "(id INTEGER PRIMARY KEY,"
+                           " title VARCHAR DEFAULT 'Default Title')")
+        connection.execute("CREATE TABLE bar "
+                           "(id INTEGER PRIMARY KEY,"
+                           " foo_id INTEGER, title VARCHAR)")