3 files changed, 10 insertions, 2 deletions
diff --git a/lib/sqlalchemy/testing/assertions.py b/lib/sqlalchemy/testing/assertions.py
index 1e8559c1a..2b305b98a 100644
--- a/lib/sqlalchemy/testing/assertions.py
+++ b/lib/sqlalchemy/testing/assertions.py
@@ -2,7 +2,7 @@ from __future__ import absolute_import
 
 from . import util as testutil
 from sqlalchemy import pool, orm, util
-from sqlalchemy.engine import default
+from sqlalchemy.engine import default, create_engine
 from sqlalchemy import exc as sa_exc
 from sqlalchemy.util import decorator
 from sqlalchemy import types as sqltypes, schema
@@ -183,6 +183,8 @@ class AssertsCompiledSQL(object):
                 dialect = default.DefaultDialect()
             elif dialect is None:
                 dialect = config.db.dialect
+            elif isinstance(dialect, basestring):
+                dialect = create_engine("%s://" % dialect).dialect
 
         kw = {}
         if params is not None:
diff --git a/lib/sqlalchemy/testing/fixtures.py b/lib/sqlalchemy/testing/fixtures.py
index 018276d4d..1a1204898 100644
--- a/lib/sqlalchemy/testing/fixtures.py
+++ b/lib/sqlalchemy/testing/fixtures.py
@@ -202,7 +202,6 @@ class TablesTest(TestBase):
 
 
 class _ORMTest(object):
-    __requires__ = ('subqueries',)
 
     @classmethod
     def teardown_class(cls):
diff --git a/lib/sqlalchemy/testing/requirements.py b/lib/sqlalchemy/testing/requirements.py
index 4df2163b7..fa617025f 100644
--- a/lib/sqlalchemy/testing/requirements.py
+++ b/lib/sqlalchemy/testing/requirements.py
@@ -55,6 +55,12 @@ class SuiteRequirements(Requirements):
         return exclusions.open()
 
     @property
+    def subqueries(self):
+        """Target database must support subqueries."""
+
+        return exclusions.open()
+
+    @property
     def autoincrement_insert(self):
         """target platform generates new surrogate integer primary key values
         when insert() is executed, excluding the pk column."""
@@ -65,6 +71,7 @@ class SuiteRequirements(Requirements):
     def returning(self):
         """target platform supports RETURNING."""
 
+        self.config.db.connect()
         return exclusions.only_if(
                 lambda: self.config.db.dialect.implicit_returning,
                 "'returning' not supported by database"