apply patch for issue #72 by asuffield@gmail.com

fixes #72

migrate/tests/versioning/test_util.py

@@ -9,6 +9,7 @@ from migrate.exceptions import MigrateDeprecationWarning
 from migrate.tests import fixture
 from migrate.tests.fixture.warnings import catch_warnings
 from migrate.versioning.util import *
+from migrate.versioning import api
 
 import warnings
 
@@ -63,6 +64,15 @@ class TestUtil(fixture.Pathed):
         # unsupported argument
         self.assertRaises(ValueError, construct_engine, 1)
 
+    def test_passing_engine(self):
+        repo = self.tmp_repos()
+        api.create(repo, 'temp')
+        api.script('First Version', repo)
+        engine = construct_engine('sqlite:///:memory:')
+        
+        api.version_control(engine, repo)
+        api.upgrade(engine, repo)
+
     def test_asbool(self):
         """test asbool parsing"""
         result = asbool(True)

migrate/versioning/util/__init__.py

@@ -158,7 +158,7 @@ def with_engine(f, *a, **kw):
         kw['engine'] = engine
         return f(*a, **kw)
     finally:
-        if isinstance(engine, Engine):
+        if isinstance(engine, Engine) and engine is not url:
             log.debug('Disposing SQLAlchemy engine %s', engine)
             engine.dispose()