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, 114 insertions, 0 deletions

diff --git a/lib/sqlalchemy/dialects/oracle/provision.py b/lib/sqlalchemy/dialects/oracle/provision.py
new file mode 100644
index 000000000..8fc2ac235
--- /dev/null
+++ b/lib/sqlalchemy/dialects/oracle/provision.py
@@ -0,0 +1,114 @@
+import logging
+
+from ... import create_engine
+from ... import exc
+from ...engine import url as sa_url
+from ...testing.provision import configure_follower
+from ...testing.provision import create_db
+from ...testing.provision import drop_db
+from ...testing.provision import follower_url_from_main
+from ...testing.provision import run_reap_dbs
+from ...testing.provision import temp_table_keyword_args
+from ...testing.provision import update_db_opts
+
+
+log = logging.getLogger(__name__)
+
+
+@create_db.for_db("oracle")
+def _oracle_create_db(cfg, eng, ident):
+    # NOTE: make sure you've run "ALTER DATABASE default tablespace users" or
+    # similar, so that the default tablespace is not "system"; reflection will
+    # fail otherwise
+    with eng.connect() as conn:
+        conn.execute("create user %s identified by xe" % ident)
+        conn.execute("create user %s_ts1 identified by xe" % ident)
+        conn.execute("create user %s_ts2 identified by xe" % ident)
+        conn.execute("grant dba to %s" % (ident,))
+        conn.execute("grant unlimited tablespace to %s" % ident)
+        conn.execute("grant unlimited tablespace to %s_ts1" % ident)
+        conn.execute("grant unlimited tablespace to %s_ts2" % ident)
+
+
+@configure_follower.for_db("oracle")
+def _oracle_configure_follower(config, ident):
+    config.test_schema = "%s_ts1" % ident
+    config.test_schema_2 = "%s_ts2" % ident
+
+
+def _ora_drop_ignore(conn, dbname):
+    try:
+        conn.execute("drop user %s cascade" % dbname)
+        log.info("Reaped db: %s", dbname)
+        return True
+    except exc.DatabaseError as err:
+        log.warning("couldn't drop db: %s", err)
+        return False
+
+
+@drop_db.for_db("oracle")
+def _oracle_drop_db(cfg, eng, ident):
+    with eng.connect() as conn:
+        # cx_Oracle seems to occasionally leak open connections when a large
+        # suite it run, even if we confirm we have zero references to
+        # connection objects.
+        # while there is a "kill session" command in Oracle,
+        # it unfortunately does not release the connection sufficiently.
+        _ora_drop_ignore(conn, ident)
+        _ora_drop_ignore(conn, "%s_ts1" % ident)
+        _ora_drop_ignore(conn, "%s_ts2" % ident)
+
+
+@update_db_opts.for_db("oracle")
+def _oracle_update_db_opts(db_url, db_opts):
+    pass
+
+
+@run_reap_dbs.for_db("oracle")
+def _reap_oracle_dbs(url, idents):
+    log.info("db reaper connecting to %r", url)
+    eng = create_engine(url)
+    with eng.connect() as conn:
+
+        log.info("identifiers in file: %s", ", ".join(idents))
+
+        to_reap = conn.execute(
+            "select u.username from all_users u where username "
+            "like 'TEST_%' and not exists (select username "
+            "from v$session where username=u.username)"
+        )
+        all_names = {username.lower() for (username,) in to_reap}
+        to_drop = set()
+        for name in all_names:
+            if name.endswith("_ts1") or name.endswith("_ts2"):
+                continue
+            elif name in idents:
+                to_drop.add(name)
+                if "%s_ts1" % name in all_names:
+                    to_drop.add("%s_ts1" % name)
+                if "%s_ts2" % name in all_names:
+                    to_drop.add("%s_ts2" % name)
+
+        dropped = total = 0
+        for total, username in enumerate(to_drop, 1):
+            if _ora_drop_ignore(conn, username):
+                dropped += 1
+        log.info(
+            "Dropped %d out of %d stale databases detected", dropped, total
+        )
+
+
+@follower_url_from_main.for_db("oracle")
+def _oracle_follower_url_from_main(url, ident):
+    url = sa_url.make_url(url)
+    url.username = ident
+    url.password = "xe"
+    return url
+
+
+@temp_table_keyword_args.for_db("oracle")
+def _oracle_temp_table_keyword_args(cfg, eng):
+    return {
+        "prefixes": ["GLOBAL TEMPORARY"],
+        "oracle_on_commit": "PRESERVE ROWS",
+    }