Create initial 2.0 engine implementation

Implemented the SQLAlchemy 2 :func:`.future.create_engine` function which
is used for forwards compatibility with SQLAlchemy 2.   This engine
features always-transactional behavior with autobegin.

Allow execution options per statement execution.  This includes
that the before_execute() and after_execute() events now accept
an additional dictionary with these options, empty if not
passed; a legacy event decorator is added for backwards compatibility
which now also emits a deprecation warning.

Add some basic tests for execution, transactions, and
the new result object.   Build out on a new testing fixture
that swaps in the future engine completely to start with.

Change-Id: I70e7338bb3f0ce22d2f702537d94bb249bd9fb0a
Fixes: #4644

1 files changed, 4 insertions, 2 deletions

diff --git a/lib/sqlalchemy/dialects/postgresql/base.py b/lib/sqlalchemy/dialects/postgresql/base.py
index f9b3d9b95..20540ac02 100644
--- a/lib/sqlalchemy/dialects/postgresql/base.py
+++ b/lib/sqlalchemy/dialects/postgresql/base.py
@@ -2753,7 +2753,7 @@ class PGDialect(default.DefaultDialect):
         s = s.columns(oid=sqltypes.Integer)
         if schema:
             s = s.bindparams(sql.bindparam("schema", type_=sqltypes.Unicode))
-        c = connection.execute(s, table_name=table_name, schema=schema)
+        c = connection.execute(s, dict(table_name=table_name, schema=schema))
         table_oid = c.scalar()
         if table_oid is None:
             raise exc.NoSuchTableError(table_name)
@@ -3519,7 +3519,9 @@ class PGDialect(default.DefaultDialect):
                 pgd.objoid = :table_oid
         """
 
-        c = connection.execute(sql.text(COMMENT_SQL), table_oid=table_oid)
+        c = connection.execute(
+            sql.text(COMMENT_SQL), dict(table_oid=table_oid)
+        )
         return {"text": c.scalar()}
 
     @reflection.cache