apply to :class:`.CheckConstraint` objects that are associated
directly with a :class:`.Column` instead of just on the
:class:`.Table`.

where the name of a check constraint making use of the
`"%(constraint_name)s"` token would get doubled up for the
constraint generated by a boolean or enum type, and overall
duplicate events would cause the `"%(constraint_name)s"` token
to keep compounding itself.
fixes #2991

is currently being supported in addition to nose, and will likely
be preferred to nose going forward.   The nose plugin system used
by SQLAlchemy has been split out so that it works under pytest as
well.  There are no plans to drop support for nose at the moment
and we hope that the test suite itself can continue to remain as
agnostic of testing platform as possible.  See the file
README.unittests.rst for updated information on running tests
with pytest.

The test plugin system has also been enhanced to support running
tests against mutiple database URLs at once, by specifying the ``--db``
and/or ``--dburi`` flags multiple times.  This does not run the entire test
suite for each database, but instead allows test cases that are specific
to certain backends make use of that backend as the test is run.
When using pytest as the test runner, the system will also run
specific test suites multiple times, once for each database, particularly
those tests within the "dialect suite".   The plan is that the enhanced
system will also be used by Alembic, and allow Alembic to run
migration operation tests against multiple backends in one run, including
third-party backends not included within Alembic itself.
Third party dialects and extensions are also encouraged to standardize
on SQLAlchemy's test suite as a basis; see the file README.dialects.rst
for background on building out from SQLAlchemy's test platform.

constructs has been enhanced in order to assist with existing
schemes that rely upon addition of ad-hoc keyword arguments to
constructs.
- To suit the use case of allowing custom arguments at construction time,
the :meth:`.DialectKWArgs.argument_for` method now allows this registration.
fixes #2962

would fail if the referred table in a foreign key contained a schema
name.  Pull request courtesy Thomas Farvour. pullreq github:67

the schema target of a :class:`.ForeignKey` will not be changed unless
that schema matches that of the parent table.  That is, if
a table "schema_a.user" has a foreign key to "schema_b.order.id",
the "schema_b" target will be maintained whether or not the
"schema" argument is passed to :meth:`.Table.tometadata`.  However
if a table "schema_a.user" refers to "schema_a.order.id", the presence
of "schema_a" will be updated on both the parent and referred tables.
This is a behavioral change hence isn't likely to be backported to
0.8; it is assumed that the previous behavior is pretty buggy
however and that it's unlikely anyone was relying upon it.

Additionally, a new parameter has been added
:paramref:`.Table.tometadata.referred_schema_fn`.  This refers to a
callable function which will be used to determine the new referred
schema for any :class:`.ForeignKeyConstraint` encountered in the
tometadata operation.  This callable can be used to revert to the
previous behavior or to customize how referred schemas are treated
on a per-constraint basis.  [ticket:2913]

- rework the tests in test.sql.test_metadata, all the "tometadata" tests
now under new class ToMetaDataTest

applied to :class:`.Constraint` and :class:`.Index` objects.  Based
on a recipe in the wiki, the new feature uses schema-events to set up
names as various schema objects are associated with each other.  The
events then expose a configuration system through a new argument
:paramref:`.MetaData.naming_convention`.  This system allows production
of both simple and custom naming schemes for constraints and indexes
on a per-:class:`.MetaData` basis.  [ticket:2923]

commit 7e65e52c086652de3dd3303c723f98f09af54db8
Author: Mike Bayer <mike_mp@zzzcomputing.com>
Date:   Sat Feb 1 15:09:04 2014 -0500

    - first pass at new naming approach

reflection now updates the PKC in place.
- support the use case of the empty PrimaryKeyConstraint in order to specify
constraint options; the columns marked as primary_key=True will now be gathered
into the columns collection, rather than being ignored. [ticket:2910]
- add validation such that column specification should only take place
in the PrimaryKeyConstraint directly, or by using primary_key=True flags;
if both are present, they have to match exactly, otherwise the condition is
assumed to be ambiguous, and a warning is emitted; the old behavior of
using the PKC columns only is maintained.

now represents exactly the kwargs that were passed, and not the defaults.
the defaults are still in dialect_options.  This allows repr() schemes such as that
of alembic to not need to look through and compare for defaults.

- clean up some shenanigans in reflection