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PostgreSQL testing utility. Both Python 2.7 and 3.3+ are supported.

To installtestgres, run:

pip install testgres

We encourage you to usevirtualenv for your testing environment.

Note: by default testgres runsinitdb,pg_ctl,psql provided byPATH.

There are several ways to specify a custom postgres installation:

• exportPG_CONFIG environment variable pointing to thepg_config executable;
• exportPG_BIN environment variable pointing to the directory with executable files.

Example:

export PG_BIN=$HOME/pg_10/binpython my_tests.py

By default,cleanup() removes all temporary files (DB files, logs etc) that were created by testgres' API methods.If you'd like to keep logs, executeconfigure_testgres(node_cleanup_full=False) before running any tests.

Note: context managers (akawith) callstop() andcleanup() automatically.

testgres supportspython logging,which means that you can aggregate logs from several nodes into one file:

importlogging# write everything to /tmp/testgres.loglogging.basicConfig(filename='/tmp/testgres.log')# create two different nodes with loggingnode1=testgres.get_new_node(use_logging=True).init().start()node2=testgres.get_new_node(use_logging=True).init().start()# execute a few queriesnode1.execute('postgres','select 1')node2.execute('postgres','select 2')

Here is an example of what you can do withtestgres:

withtestgres.get_new_node('test')asnode:node.init()# run initdbnode.start()# start PostgreSQLprint(node.execute('postgres','select 1'))node.stop()# stop PostgreSQL

Let's walk through the code. First, you create a new node using:

withtestgres.get_new_node('master')asnode:

or

withtestgres.get_new_node('master','/path/to/DB')asnode:

wheremaster is a node's application name. Name matters if you're testing something like replication.Functionget_new_node() only creates directory structure in specified directory (or somewhere in '/tmp' ifwe did not specify base directory) for cluster. After that, we have to initialize the PostgreSQL cluster:

node.init()

This function runsinitdb command and adds some basic configuration topostgresql.conf andpg_hba.conf files.Functioninit() accepts optional parameterallows_streaming which configures cluster for streaming replication (default isFalse).Now we are ready to start:

node.start()

Finally, our temporary cluster is able to process queries. There are four ways to run them:

The last one is the most powerful: you can usebegin(isolation_level),commit() androllback():

withnode.connect()ascon:con.begin('serializable')print(con.execute('select %s',1))con.rollback()

To stop the server, run:

node.stop()

It's quite easy to create a backup and start a new replica:

withtestgres.get_new_node('master')asmaster:master.init().start()withmaster.backup()asbackup:# create and start a new replicareplica=backup.spawn_replica('replica').start()# catch up with master nodereplica.catchup()# execute a dummy queryprint(replica.execute('postgres','select 1'))

testgres also can help you to make benchmarks usingpgbench from postgres installation:

withtestgres.get_new_node('master')asmaster:# start a new nodemaster.init().start()# initialize default DB and run bench for 10 secondsres=master.pgbench_init(scale=2).pgbench_run(time=10)print(res)

Ildar Musin <i.musin(at)postgrespro.ru> Postgres Professional Ltd., Russia
Dmitry Ivanov <d.ivanov(at)postgrespro.ru> Postgres Professional Ltd., Russia
Ildus Kurbangaliev <i.kurbangaliev(at)postgrespro.ru> Postgres Professional Ltd., Russia
Yury Zhuravlev <stalkerg(at)gmail.com>