Merge branch 'ticket_2587'

Conflicts:
	test/profiles.txt
	test/sql/test_selectable.py

1 files changed, 10 insertions, 5 deletions

diff --git a/lib/sqlalchemy/testing/assertions.py b/lib/sqlalchemy/testing/assertions.py
index c04153961..96a8bc023 100644
--- a/lib/sqlalchemy/testing/assertions.py
+++ b/lib/sqlalchemy/testing/assertions.py
@@ -184,15 +184,20 @@ class AssertsCompiledSQL(object):
                         allow_dialect_select=False):
         if use_default_dialect:
             dialect = default.DefaultDialect()
-        elif dialect == None and not allow_dialect_select:
-            dialect = getattr(self, '__dialect__', None)
-            if dialect == 'default':
-                dialect = default.DefaultDialect()
-            elif dialect is None:
+        elif allow_dialect_select:
+            dialect = None
+        else:
+            if dialect is None:
+                dialect = getattr(self, '__dialect__', None)
+
+            if dialect is None:
                 dialect = config.db.dialect
+            elif dialect == 'default':
+                dialect = default.DefaultDialect()
             elif isinstance(dialect, util.string_types):
                 dialect = create_engine("%s://" % dialect).dialect
 
+
         kw = {}
         if params is not None:
             kw['column_keys'] = list(params)