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Postgres testing utility

To installtestgres run:

pip install testgres

At current state it only works with Python 2.*

Node: by default testgres runsinitdb,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 usetestgres.

fromtestgresimportget_new_nodetry:node=get_new_node('master')node.init()node.start()stdout=node.safe_psql('postgres','SELECT 1')printstdoutnode.stop()exceptClusterException,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. Functionget_new_node() only creates directory structure in/tmp for cluster. Next line:

node.init()

initializes cluster. On low level it 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()

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

• node.psql(database, query) - runs query viapsql command and returns tuple (error code, stdout, stderr)
• node.safe_psql(database, query) - the same aspsql() except that it returns onlystdout. If error occures during the execution then it will throw an exception;
• node.execute(database, query) - connects with postgresql server usingpsycopg2 orpg8000 library (depends on which is installed in your system) and returns two-dimensional array with data.

To stop server run:

node.stop()

Please seetestgres/tests directory for replication configuration example.