diff --git a/migrate/tests/changeset/test_changeset.py b/migrate/tests/changeset/test_changeset.py
index d94f6ca..3989ea3 100644
--- a/migrate/tests/changeset/test_changeset.py
+++ b/migrate/tests/changeset/test_changeset.py
@@ -7,6 +7,7 @@ from sqlalchemy import *
 
 from migrate import changeset, exceptions
 from migrate.changeset import *
+from migrate.changeset import constraint
 from migrate.changeset.schema import ColumnDelta
 from migrate.tests import fixture
 from migrate.tests.fixture.warnings import catch_warnings
@@ -168,7 +169,7 @@ class TestAddDropColumn(fixture.DB):
         reftable.create()
 
         # create column with fk
-        col = Column('data', Integer, ForeignKey(reftable.c.id))
+        col = Column('data', Integer, ForeignKey(reftable.c.id, name='testfk'))
         col.create(self.table)
 
         # check if constraint is added
@@ -186,6 +187,11 @@ class TestAddDropColumn(fixture.DB):
         else:
             self.assertEqual(reftable.c.id.name,
                 col.foreign_keys[0].column.name)
+
+        if self.engine.name == 'mysql':
+            constraint.ForeignKeyConstraint([self.table.c.data],
+                                            [reftable.c.id],
+                                            name='testfk').drop()
         col.drop(self.table)
 
         if self.engine.has_table(reftable.name):
@@ -384,8 +390,8 @@ class TestAddDropColumn(fixture.DB):
         self.table = Table(
             self.table_name, self.meta,
             Column('id', Integer, primary_key=True),
-            Column('r1', Integer, ForeignKey('tmp_ref.id')),
-            Column('r2', Integer, ForeignKey('tmp_ref.id')),
+            Column('r1', Integer, ForeignKey('tmp_ref.id', name='test_fk1')),
+            Column('r2', Integer, ForeignKey('tmp_ref.id', name='test_fk2')),
             )
         self.table.create()
 
@@ -394,6 +400,9 @@ class TestAddDropColumn(fixture.DB):
                          self._actual_foreign_keys())
         
         # delete one
+        if self.engine.name == 'mysql':
+            constraint.ForeignKeyConstraint([self.table.c.r2], [reftable.c.id],
+                                            name='test_fk2').drop()
         self.table.c.r2.drop()
         
         # check remaining foreign key is there
@@ -435,6 +444,10 @@ class TestAddDropColumn(fixture.DB):
                          self._actual_foreign_keys())
         
         # delete one
+        if self.engine.name == 'mysql':
+            constraint.ForeignKeyConstraint([self.table.c.r1, self.table.c.r2],
+                                            [reftable.c.id, reftable.c.jd],
+                                            name='test_fk').drop()
         self.table.c.r2.drop()
         
         # check the constraint is gone, since part of it
diff --git a/migrate/tests/fixture/database.py b/migrate/tests/fixture/database.py
index b9eb0ca..e000d60 100644
--- a/migrate/tests/fixture/database.py
+++ b/migrate/tests/fixture/database.py
@@ -6,6 +6,7 @@ import logging
 from decorator import decorator
 
 from sqlalchemy import create_engine, Table, MetaData
+from sqlalchemy import exc as sa_exc
 from sqlalchemy.orm import create_session
 from sqlalchemy.pool import StaticPool
 
@@ -81,13 +82,17 @@ def usedb(supported=None, not_supported=None):
             try:
                 log.debug("Running test with engine %s", url)
                 try:
-                    try:
-                        self._setup(url)
-                    except Exception,e:
-                        setup_exception=e
-                    else:
-                        setup_exception=None
-                        f(self, *a, **kw)
+                    self._setup(url)
+                except sa_exc.OperationalError:
+                    log.info('Backend %s is not available, skip it', url)
+                    continue
+                except Exception as e:
+                    setup_exception = e
+                else:
+                    setup_exception = None
+
+                try:
+                    f(self, *a, **kw)
                 finally:
                     try:
                         self._teardown()
diff --git a/test_db.cfg b/test_db.cfg
index f628826..7691816 100644
--- a/test_db.cfg
+++ b/test_db.cfg
@@ -8,7 +8,7 @@
 # The string '__tmp__' is substituted for a temporary file in each connection
 # string. This is useful for sqlite tests.
 sqlite:///__tmp__
-#postgresql://postgres@localhost/testdb
-#mysql://root@localhost/testdb
+postgresql://openstack_citest:openstack_citest@localhost/openstack_citest
+mysql://openstack_citest:openstack_citest@localhost/openstack_citest
 #oracle://scott:tiger@localhost
 #firebird://scott:tiger@localhost//var/lib/firebird/databases/test_migrate
diff --git a/tox.ini b/tox.ini
index 1107e6c..88f00db 100644
--- a/tox.ini
+++ b/tox.ini
@@ -10,7 +10,7 @@ setenv = VIRTUAL_ENV={envdir}
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
 commands =
-  python setup.py testr --slowest --testr-args='{posargs}'
+  python setup.py testr --slowest --testr-args='{posargs} --concurrency=1'
 
 [testenv:py26sa07]
 basepython = python2.6