java-design-patterns/object-mother/README.md

---
layout: pattern
title: Object Mother
folder: object-mother
permalink: /patterns/object-mother/
categories: Creational
language: en
tags:
 - Instantiation
---

## Object Mother
Define a factory of immutable content with separated builder and factory interfaces.

## Class diagram
![alt text](./etc/object-mother.png "Object Mother")

## Applicability
Use the Object Mother pattern when

* You want consistent objects over several tests
* You want to reduce code for creation of objects in tests
* Every test should run with fresh data

## Credits

* [Answer by David Brown](http://stackoverflow.com/questions/923319/what-is-an-objectmother) to the stackoverflow question: [What is an ObjectMother?](http://stackoverflow.com/questions/923319/what-is-an-objectmother)
* [c2wiki - Object Mother](http://c2.com/cgi/wiki?ObjectMother)
* [Nat Pryce - Test Data Builders: an alternative to the Object Mother pattern](http://www.natpryce.com/articles/000714.html)
Initial commit of the object mother #498 Add a simple king and queen classes which implement the behaviour of the royalty interface. Also wrote the object mother of royalty objects which is final so you can just call the static methods in it to create objects with a specific state to use them fast in tests. The tests are already created for testing the behaviour and the type of the objects which are created by the object mother. I also created the UML diagrams via object aid and updated the readme. 2016-10-04 22:33:06 +02:00			`---`
			`layout: pattern`
			`title: Object Mother`
			`folder: object-mother`
			`permalink: /patterns/object-mother/`
			`categories: Creational`
fix: Fixed pages showing up in wrong language (#1752) * Fix languages * Missed change for version number * Add language field for presentation * Revert change in README for double buffer Co-authored-by: Jackie Nim <=> 2021-05-19 10:49:05 -06:00			`language: en`
Initial commit of the object mother #498 Add a simple king and queen classes which implement the behaviour of the royalty interface. Also wrote the object mother of royalty objects which is final so you can just call the static methods in it to create objects with a specific state to use them fast in tests. The tests are already created for testing the behaviour and the type of the objects which are created by the object mother. I also created the UML diagrams via object aid and updated the readme. 2016-10-04 22:33:06 +02:00			`tags:`
https://github.com/iluwatar/java-design-patterns-web/issues/8 Update pattern categories and tags 2019-12-13 21:09:28 +02:00			`- Instantiation`
Initial commit of the object mother #498 Add a simple king and queen classes which implement the behaviour of the royalty interface. Also wrote the object mother of royalty objects which is final so you can just call the static methods in it to create objects with a specific state to use them fast in tests. The tests are already created for testing the behaviour and the type of the objects which are created by the object mother. I also created the UML diagrams via object aid and updated the readme. 2016-10-04 22:33:06 +02:00			`---`

			`## Object Mother`
			`Define a factory of immutable content with separated builder and factory interfaces.`

#1113 Link uml-reverse-mapper created class diagrams to readme, where needed 2019-12-07 20:01:13 +02:00			`## Class diagram`
Initial commit of the object mother #498 Add a simple king and queen classes which implement the behaviour of the royalty interface. Also wrote the object mother of royalty objects which is final so you can just call the static methods in it to create objects with a specific state to use them fast in tests. The tests are already created for testing the behaviour and the type of the objects which are created by the object mother. I also created the UML diagrams via object aid and updated the readme. 2016-10-04 22:33:06 +02:00			`![alt text](./etc/object-mother.png "Object Mother")`

			`## Applicability`
			`Use the Object Mother pattern when`

			`* You want consistent objects over several tests`
https://github.com/iluwatar/java-design-patterns-web/issues/8 Update pattern categories and tags 2019-12-13 21:09:28 +02:00			`* You want to reduce code for creation of objects in tests`
			`* Every test should run with fresh data`
Initial commit of the object mother #498 Add a simple king and queen classes which implement the behaviour of the royalty interface. Also wrote the object mother of royalty objects which is final so you can just call the static methods in it to create objects with a specific state to use them fast in tests. The tests are already created for testing the behaviour and the type of the objects which are created by the object mother. I also created the UML diagrams via object aid and updated the readme. 2016-10-04 22:33:06 +02:00
			`## Credits`

			`* [Answer by David Brown](http://stackoverflow.com/questions/923319/what-is-an-objectmother) to the stackoverflow question: [What is an ObjectMother?](http://stackoverflow.com/questions/923319/what-is-an-objectmother)`
			`* [c2wiki - Object Mother](http://c2.com/cgi/wiki?ObjectMother)`
Work on #190: urm/puml updates * added pumlid where it was missing and possible * removed pumlid where it generated a bad image * regenerated some incorrect puml's * added 'left to right direction' puml prefix to some diagrams to improve the automatic layouting 2017-03-25 22:07:10 +01:00			`* [Nat Pryce - Test Data Builders: an alternative to the Object Mother pattern](http://www.natpryce.com/articles/000714.html)`