Postgres testing utility

To install testgres run:

pip install testgres

At current state it only works with Python 2.*

Node: by default testgres runs initdb, pg_ctl, psql commands from the $PATH. To specify custom postgres installation set environment variable $PG_CONFIG and point it to pg_config executable: export PG_CONFIG=/path/to/pg_config

Here is an example of how you can use testgres.

from testgres import get_new_node

try:
    node = get_new_node('master')
    node.init()
    node.start()
    stdout = node.safe_psql('postgres', 'SELECT 1')
    print stdout
    node.stop()
except ClusterException, e:
    node.cleanup()

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

node = get_new_node('master')

master here is a node's name, not the database's name. The name matters if you're testing replication. Function get_new_node() only creates directory structure in /tmp for cluster. Next line:

node.init()

initializes cluster. On low level it runs initdb command and adds some basic configuration to postgresql.conf and pg_hba.conf files. Function init() accepts optional parameter allows_streaming which configures cluster for streaming replication (default is False). Now we are ready to start:

node.start()

After this you are able to run queries over the cluster. There are three functions to do that:

• node.psql(database, query) - runs query via psql command and returns tuple (error code, stdout, stderr)
• node.safe_psql(database, query) - the same as psql() except that it returns only stdout. If error occures during the execution then it will throw an exception;
• node.execute(database, query) - connects with postgresql server using psycopg2 or pg8000 library (depends on which is installed in your system) and returns two-dimensional array with data.

To stop server run:

node.stop()

Please see testgres/tests directory for replication configuration example.