white-noise

Test Data generator for SQLAlchemy and Django

This package is designed to make it easy to generate test data for SQLAlchemy or Django applications. It was inspired after spending most of a day failing to get Mixer working properly.

The aim is to have a consistant, simple API for all generation.

API overview

Fixtures define the data that should be entered into the database. Generators create the data and a fixture runner enters it.

Fixtures

A fixture object takes 4 parameters.

• model The model to be acted on. This should be a direct reference to the model class that data should be created for.

• quantity How many instances of the model need adding to the database

• dependencies A list of fixtures that this fixture depends on. The base for fixture runners can resolve dependencies to ensure fixtures are ruin in the correct order

• fields This is a dictionary of field names to generator instances. The field name is the field of the model to be generated, where generator is a generator to be used (it is normal to instansiate the generator in the fields list)

Generators

Currently available generators (and their options)

LiteralGenerator

Returns a literal value that is passed

• value The value to return

RandomGenerator

Creates a random string for the field

• length The length of the field

LipsumGenerator

Creates a semi-random string sentence of the Lorem Ipsum form

InsultGenerator

Creates a random insulting sentence string for the field

SequenceGenerator

Iterates over a sequence. Loops if the end of the sequence is reached.

• values The values to use. Can be any iterable (lists, tuples, generators, etc.)

sqlalchemy.SelectGenerator

Selects an object from the database and uses that as the value for the field This is for creating objects with relationships to others in the database (e.g. foreign keys)

This generator only works with the SQLAlchemy fixture runner. (if writting your own fixture runner it must receive an SQLAlchemy session object as well as its options)

• model The foreign model to select from

• random Select randomly or select the first (default => random)

sqlalchemy.LinkGenerator

Selects a list of objects from the database and uses that as the value for the field This is for creating objects with many-to-many relationships to others in the database (e.g. link tables/association tables)

This generator only works with the SQLAlchemy fixture runner. (if writting your own fixture runner it must receive an SQLAlchemy session object as well as its options)

• model The foreign model to select from

• random Select randomly or select the first (default => random)

• max_map Select randomly up to max_map associations (default -> 1)

• unique_maps Generate unique map using memory of previously chosen association maps. (default => False)

• max_iter Limit the number of iterations for searching unique map. (default -> 100)

Fixture runners

SQLAlchemyFixtureRunner

Runs the fixtures using SQLAlchemy models. This class must be instantiated with a reference to a SQLAlchemy session object to be used for accessing the database

DjangoFixtureRunner

Runs the fixtures against a Django database. It must be run in a django context (e.g. from a custom management command)

A Django management command is included. To use it, add 'whitenoise' to your installed apps