- add begin_transaction() env.py helper. Emits the appropriate

begin/commit pair regardless of context.
- add dialect support for BEGIN/COMMIT working corresponding
to backend.  Add implementation for SQL server.
- add tests for BEGIN/COMMIT , #11
- rework SQL server test suite for more classes of test
- fix test suite to clean up after a prior failed suite

3 files changed, 100 insertions, 58 deletions

diff --git a/tests/__init__.py b/tests/__init__.py
index e44e23b..0c35747 100644
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -14,6 +14,7 @@ import ConfigParser
 from nose import SkipTest
 from sqlalchemy.exc import SQLAlchemyError
 from sqlalchemy.util import decorator
+import shutil
 
 staging_directory = os.path.join(os.path.dirname(__file__), 'scratch')
 files_directory = os.path.join(os.path.dirname(__file__), 'files')
@@ -74,9 +75,13 @@ def assert_compiled(element, assert_string, dialect=None):
         assert_string.replace("\n", "").replace("\t", "")
     )
 
-def capture_context_buffer():
+def capture_context_buffer(transactional_ddl=None):
     buf = StringIO.StringIO()
 
+    if transactional_ddl is not None:
+        context._context_opts['transactional_ddl'] = \
+            transactional_ddl
+
     class capture(object):
         def __enter__(self):
             context._context_opts['output_buffer'] = buf
@@ -210,13 +215,13 @@ datefmt = %%H:%%M:%%S
     """ % (dir_, dir_))
 
 
-def no_sql_testing_config():
+def no_sql_testing_config(dialect="postgresql"):
     """use a postgresql url with no host so that connections guaranteed to fail"""
     dir_ = os.path.join(staging_directory, 'scripts')
     return _write_config_file("""
 [alembic]
 script_location = %s
-sqlalchemy.url = postgresql://
+sqlalchemy.url = %s://
 
 [loggers]
 keys = root
@@ -242,7 +247,7 @@ keys = generic
 format = %%(levelname)-5.5s [%%(name)s] %%(message)s
 datefmt = %%H:%%M:%%S
 
-""" % (dir_))
+""" % (dir_, dialect))
 
 def _write_config_file(text):
     cfg = _testing_config()
@@ -254,7 +259,10 @@ def staging_env(create=True, template="generic"):
     from alembic import command, script
     cfg = _testing_config()
     if create:
-        command.init(cfg, os.path.join(staging_directory, 'scripts'))
+        path = os.path.join(staging_directory, 'scripts')
+        if os.path.exists(path):
+            shutil.rmtree(path)
+        command.init(cfg, path)
     sc = script.ScriptDirectory.from_config(cfg)
     context._opts(cfg,sc, fn=lambda:None)
     return sc
diff --git a/tests/test_mssql.py b/tests/test_mssql.py
index ab546e6..9392c6c 100644
--- a/tests/test_mssql.py
+++ b/tests/test_mssql.py
@@ -1,60 +1,83 @@
 """Test op functions against MSSQL."""
 
-from tests import op_fixture
-from alembic import op
+from tests import op_fixture, capture_context_buffer, no_sql_testing_config, staging_env, three_rev_fixture, clear_staging_env
+from alembic import op, command
 from sqlalchemy import Integer, Column, ForeignKey, \
             UniqueConstraint, Table, MetaData, String
 from sqlalchemy.sql import table
+from unittest import TestCase
 
-def test_add_column():
-    context = op_fixture('mssql')
-    op.add_column('t1', Column('c1', Integer, nullable=False))
-    context.assert_("ALTER TABLE t1 ADD c1 INTEGER NOT NULL")
-
-def test_add_column_with_default():
-    context = op_fixture("mssql")
-    op.add_column('t1', Column('c1', Integer, nullable=False, server_default="12"))
-    context.assert_("ALTER TABLE t1 ADD c1 INTEGER NOT NULL DEFAULT '12'")
-
-def test_alter_column_rename_mssql():
-    context = op_fixture('mssql')
-    op.alter_column("t", "c", name="x")
-    context.assert_(
-        "EXEC sp_rename 't.c', 'x', 'COLUMN'"
-    )
-
-def test_drop_column_w_default():
-    context = op_fixture('mssql')
-    op.drop_column('t1', 'c1', mssql_drop_default=True)
-    context.assert_contains("exec('alter table t1 drop constraint ' + @const_name)")
-    context.assert_contains("ALTER TABLE t1 DROP COLUMN c1")
-
-
-def test_drop_column_w_check():
-    context = op_fixture('mssql')
-    op.drop_column('t1', 'c1', mssql_drop_check=True)
-    context.assert_contains("exec('alter table t1 drop constraint ' + @const_name)")
-    context.assert_contains("ALTER TABLE t1 DROP COLUMN c1")
-
-def test_alter_column_nullable():
-    context = op_fixture('mssql')
-    op.alter_column("t", "c", nullable=True)
-    context.assert_(
-        "ALTER TABLE t ALTER COLUMN c NULL"
-    )
-
-def test_alter_column_not_nullable():
-    context = op_fixture('mssql')
-    op.alter_column("t", "c", nullable=False)
-    context.assert_(
-        "ALTER TABLE t ALTER COLUMN c SET NOT NULL"
-    )
-
-# TODO: when we add schema support
-#def test_alter_column_rename_mssql_schema():
-#    context = op_fixture('mssql')
-#    op.alter_column("t", "c", name="x", schema="y")
-#    context.assert_(
-#        "EXEC sp_rename 'y.t.c', 'x', 'COLUMN'"
-#    )
+
+class FullEnvironmentTests(TestCase):
+    @classmethod
+    def setup_class(cls):
+        env = staging_env()
+        cls.cfg = cfg = no_sql_testing_config("mssql")
+
+        cls.a, cls.b, cls.c = \
+            three_rev_fixture(cfg)
+
+    @classmethod
+    def teardown_class(cls):
+        clear_staging_env()
+
+    def test_begin_comit(self):
+        with capture_context_buffer(transactional_ddl=True) as buf:
+            command.upgrade(self.cfg, self.a, sql=True)
+        assert "BEGIN TRANSACTION" in buf.getvalue()
+        assert "COMMIT" in buf.getvalue()
+
+class OpTest(TestCase):
+    def test_add_column(self):
+        context = op_fixture('mssql')
+        op.add_column('t1', Column('c1', Integer, nullable=False))
+        context.assert_("ALTER TABLE t1 ADD c1 INTEGER NOT NULL")
+
+
+    def test_add_column_with_default(self):
+        context = op_fixture("mssql")
+        op.add_column('t1', Column('c1', Integer, nullable=False, server_default="12"))
+        context.assert_("ALTER TABLE t1 ADD c1 INTEGER NOT NULL DEFAULT '12'")
+
+    def test_alter_column_rename_mssql(self):
+        context = op_fixture('mssql')
+        op.alter_column("t", "c", name="x")
+        context.assert_(
+            "EXEC sp_rename 't.c', 'x', 'COLUMN'"
+        )
+
+    def test_drop_column_w_default(self):
+        context = op_fixture('mssql')
+        op.drop_column('t1', 'c1', mssql_drop_default=True)
+        context.assert_contains("exec('alter table t1 drop constraint ' + @const_name)")
+        context.assert_contains("ALTER TABLE t1 DROP COLUMN c1")
+
+
+    def test_drop_column_w_check(self):
+        context = op_fixture('mssql')
+        op.drop_column('t1', 'c1', mssql_drop_check=True)
+        context.assert_contains("exec('alter table t1 drop constraint ' + @const_name)")
+        context.assert_contains("ALTER TABLE t1 DROP COLUMN c1")
+
+    def test_alter_column_nullable(self):
+        context = op_fixture('mssql')
+        op.alter_column("t", "c", nullable=True)
+        context.assert_(
+            "ALTER TABLE t ALTER COLUMN c NULL"
+        )
+
+    def test_alter_column_not_nullable(self):
+        context = op_fixture('mssql')
+        op.alter_column("t", "c", nullable=False)
+        context.assert_(
+            "ALTER TABLE t ALTER COLUMN c SET NOT NULL"
+        )
+
+    # TODO: when we add schema support
+    #def test_alter_column_rename_mssql_schema(self):
+    #    context = op_fixture('mssql')
+    #    op.alter_column("t", "c", name="x", schema="y")
+    #    context.assert_(
+    #        "EXEC sp_rename 'y.t.c', 'x', 'COLUMN'"
+    #    )
 
diff --git a/tests/test_sql_script.py b/tests/test_sql_script.py
index 1df94cd..a615bdf 100644
--- a/tests/test_sql_script.py
+++ b/tests/test_sql_script.py
@@ -14,6 +14,17 @@ def setup():
 def teardown():
     clear_staging_env()
 
+def test_begin_comit():
+    with capture_context_buffer(transactional_ddl=True) as buf:
+        command.upgrade(cfg, a, sql=True)
+    assert "BEGIN" in buf.getvalue()
+    assert "COMMIT" in buf.getvalue()
+
+    with capture_context_buffer(transactional_ddl=False) as buf:
+        command.upgrade(cfg, a, sql=True)
+    assert "BEGIN" not in buf.getvalue()
+    assert "COMMIT" not in buf.getvalue()
+
 def test_version_from_none_insert():
     with capture_context_buffer() as buf:
         command.upgrade(cfg, a, sql=True)