Refactor test provisioning to dialect-level files

Fixes: #5085

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Move dialect-specific provisioning code to dialect-level copies of provision.py.

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This pull request is:

- [ ] A documentation / typographical error fix
	- Good to go, no issue or tests are needed
- [x] A short code fix
	- please include the issue number, and create an issue if none exists, which
	  must include a complete example of the issue.  one line code fixes without an
	  issue and demonstration will not be accepted.
	- Please include: `Fixes: #<issue number>` in the commit message
	- please include tests.   one line code fixes without tests will not be accepted.
- [ ] A new feature implementation
	- please include the issue number, and create an issue if none exists, which must
	  include a complete example of how the feature would look.
	- Please include: `Fixes: #<issue number>` in the commit message
	- please include tests.

**Have a nice day!**

Closes: #5092
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/5092
Pull-request-sha: 25b9b7a9800549fb823576af8674e8d33ff4b2c1

Change-Id: Ie0b4a69aa472a60bdbd825e04c8595382bcc98e1

1 files changed, 84 insertions, 0 deletions

diff --git a/lib/sqlalchemy/dialects/mssql/provision.py b/lib/sqlalchemy/dialects/mssql/provision.py
new file mode 100644
index 000000000..558ad7a7a
--- /dev/null
+++ b/lib/sqlalchemy/dialects/mssql/provision.py
@@ -0,0 +1,84 @@
+import logging
+
+from ... import create_engine
+from ... import exc
+from ...testing.provision import create_db
+from ...testing.provision import drop_db
+from ...testing.provision import run_reap_dbs
+from ...testing.provision import update_db_opts
+
+
+log = logging.getLogger(__name__)
+
+
+@update_db_opts.for_db("mssql")
+def _mssql_update_db_opts(db_url, db_opts):
+    db_opts["legacy_schema_aliasing"] = False
+
+
+@create_db.for_db("mssql")
+def _mssql_create_db(cfg, eng, ident):
+    with eng.connect().execution_options(isolation_level="AUTOCOMMIT") as conn:
+        conn.execute("create database %s" % ident)
+        conn.execute(
+            "ALTER DATABASE %s SET ALLOW_SNAPSHOT_ISOLATION ON" % ident
+        )
+        conn.execute(
+            "ALTER DATABASE %s SET READ_COMMITTED_SNAPSHOT ON" % ident
+        )
+        conn.execute("use %s" % ident)
+        conn.execute("create schema test_schema")
+        conn.execute("create schema test_schema_2")
+
+
+@drop_db.for_db("mssql")
+def _mssql_drop_db(cfg, eng, ident):
+    with eng.connect().execution_options(isolation_level="AUTOCOMMIT") as conn:
+        _mssql_drop_ignore(conn, ident)
+
+
+def _mssql_drop_ignore(conn, ident):
+    try:
+        # typically when this happens, we can't KILL the session anyway,
+        # so let the cleanup process drop the DBs
+        # for row in conn.execute(
+        #     "select session_id from sys.dm_exec_sessions "
+        #        "where database_id=db_id('%s')" % ident):
+        #    log.info("killing SQL server sesssion %s", row['session_id'])
+        #    conn.execute("kill %s" % row['session_id'])
+
+        conn.execute("drop database %s" % ident)
+        log.info("Reaped db: %s", ident)
+        return True
+    except exc.DatabaseError as err:
+        log.warning("couldn't drop db: %s", err)
+        return False
+
+
+@run_reap_dbs.for_db("mssql")
+def _reap_mssql_dbs(url, idents):
+    log.info("db reaper connecting to %r", url)
+    eng = create_engine(url)
+    with eng.connect().execution_options(isolation_level="AUTOCOMMIT") as conn:
+
+        log.info("identifiers in file: %s", ", ".join(idents))
+
+        to_reap = conn.execute(
+            "select d.name from sys.databases as d where name "
+            "like 'TEST_%' and not exists (select session_id "
+            "from sys.dm_exec_sessions "
+            "where database_id=d.database_id)"
+        )
+        all_names = {dbname.lower() for (dbname,) in to_reap}
+        to_drop = set()
+        for name in all_names:
+            if name in idents:
+                to_drop.add(name)
+
+        dropped = total = 0
+        for total, dbname in enumerate(to_drop, 1):
+            if _mssql_drop_ignore(conn, dbname):
+                dropped += 1
+        log.info(
+            "Dropped %d out of %d stale databases detected", dropped, total
+        )