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PostgreSQL testing utility.

To installtestgres, run:

pip install testgres

We encourage you to usevirtualenv for your testing environment. Both Python 2.7 and 3.5 are supported.

Note: by default testgres runsinitdb,pg_ctl,psql provided by$PATH. To specify a custom postgres installation, set the environment variable$PG_CONFIG pointing to thepg_config executable:export PG_CONFIG=/path/to/pg_config.

Here is an example of what you can do withtestgres:

importtestgresnode=Nonetry:node=testgres.get_new_node('test').init().start()print(node.execute('postgres','select 1'))excepttestgres.ClusterExceptionase:print(e)finally:ifnodeisnotNone:node.cleanup()

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

node=testgres.get_new_node('master')

or:

node=testgres.get_new_node('master','/path/to/base')

master is a node's name, not the DB's name. The name matters if you're testing something like replication. Functionget_new_node() only creates directory structure in specified directory (or somewhere in '/tmp' if we 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:

• node.psql(database, query) - runs query viapsql command and returns tuple(error code, stdout, stderr)
• node.safe_psql(database, query) - same aspsql() except that it returns onlystdout. If an error occures during the execution, an exception will be thrown.
• node.execute(database, query) - connects to postgresql server usingpsycopg2 orpg8000 library (depends on which is installed in your system) and returns two-dimensional array with data.
• node.connect(database='postgres') - returns connection wrapper (NodeConnection) capable of running several queries within a single transaction.

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 is essential to clean everything up, so make sure to callnode.cleanup() once you've finished all of your tests.

Please seetestgres/tests directory for replication configuration example.

Note: you could take a look atpg_pathman to get an idea oftestgres' capabilities.

Ildar Musini.musin@postgrespro.ru Postgres Professional Ltd., RussiaDmitry Ivanovd.ivanov@postgrespro.ru Postgres Professional Ltd., Russia