AutoFixture Cheat Sheet

This page contains short code snippets that demonstrate AutoFixture features. All examples assume that a Fixture instance called fixture has previously been created like this:
var fixture = new Fixture();

Completely Anonymous String

var anonymousText = fixture.CreateAnonymous<string>();

Sample Result

string: "f5cdf6b1-a473-410f-95f3-f427f7abb0c7"

More Information

http://blog.ploeh.dk/2009/04/02/CreatingStringsWithAutoFixture.aspx

Seeded String

var anonymousName = fixture.CreateAnonymous("Name");

Sample Result

string: "Name30a35da1-d681-441b-9db3-77ff51728b58"

More Information

http://blog.ploeh.dk/2009/04/02/CreatingStringsWithAutoFixture.aspx

Anonymous Number

int anonymousNumber = fixture.CreateAnonymous<int>();

Sample Result

int: 1, followed by 2, then by 3, etc.

More Information

http://blog.ploeh.dk/2009/04/03/CreatingNumbersWithAutoFixture.aspx

Complex Type

var anonymousParent =
    fixture.CreateAnonymous<ComplexParent>();

Sample Result

ComplexParent:
->Child: ComplexChild
-->Name: string: "namef70b67ff-05d3-4498-95c9-de74e1aa0c3c"
-->Number: int: 1

More Information

http://blog.ploeh.dk/2009/03/24/HowAutoFixtureCreatesObjects.aspx

Abstract Types

fixture.Register<IMyInterface>(() => 
    new FakeMyInterface());

Sample Result

Every time the fixture instance is asked to create an instance of IMyInterface, it will return a new instance of FakeMyInterface.

More Information

http://blog.ploeh.dk/2009/04/23/DealingWithTypesWithoutPublicConstructors.aspx

Replaced Default Algorithm

fixture.TypeMappings[typeof(string)] = s => "fnaah";
string result = fixture.CreateAnonymous<string>();

Sample Result

string: "fnaah"

More Information

http://blog.ploeh.dk/2009/04/27/ReplacingAutoFixturesDefaultAlgorithms.aspx

Sequence of Strings

var strings = fixture.CreateMany<string>();

Sample Result

IEnumerable<string>:
-> string: "ecc1cc75-cd7a-417f-b477-2913802440b4"
-> string: "fce70a7b-fae5-474f-8055-415ca46eac20"
-> string: "79b45532-d66f-4abc-9311-77ba68dc9e3c"

More Information

http://blog.ploeh.dk/2009/05/11/AnonymousSequencesWithAutoFixture.aspx

Sequence of Custom Objects

var myInstances = fixture.CreateMany<MyClass>();

Sample Result

IEnumerable<MyClass>:
-> MyClass:
--> MyText: string: "MyTextfda10499-e112-476b-924a-2c7b831227f2"
-> MyClass:
--> MyText: string: "MyText6140d5f8-0639-4718-a82b-181d0410f9cf"
-> MyClass:
--> MyText: string: "MyText4a89c288-694a-4a19-a407-7348b70420cf"

More Information

http://blog.ploeh.dk/2009/05/11/AnonymousSequencesWithAutoFixture.aspx

Add to Collection

var list = new List<MyClass>();
fixture.AddManyTo(list);

Sample Result

List<MyClass>:
-> MyClass:
--> MyText: string: "MyTextca86de74-e8df-46b1-bc15-63f763ce9e07"
-> MyClass:
--> MyText: string: "MyTextc45ff7b9-b30e-4246-b535-2eb06bc888c0"
-> MyClass:
--> MyText: string: "MyTextefadfab3-0992-4ecb-a3df-c6f1d5e61f12"

More Information

http://blog.ploeh.dk/2009/05/11/AnonymousSequencesWithAutoFixture.aspx

Set Property

var mc = fixture.Build<MyClass>()
    .With(x => x.MyText, "Ploeh")
    .CreateAnonymous();

Sample Result

MyClass:
-> MyText: string: "Ploeh"

More Information

http://blog.ploeh.dk/2009/06/01/SettingPropertyValuesWhileBuildingAnonymousVariablesWithAutoFixture.aspx

Disable AutoProperties

var sut = fixture.Build<Vehicle>()
    .OmitAutoProperties()
    .CreateAnonymous();

Sample Result

Vehicle:
-> Wheels: int: 4
The Wheels property will have the default value of 4, instead of having an anonymous value assigned via its setter

More Information

http://blog.ploeh.dk/2009/07/23/DisablingAutoPropertiesInAutoFixture.aspx

Disable Property

var person = fixture.Build<Person>()
    .Without(p => p.Spouse)
    .CreateAnonymous();

Sample Result

Person:
-> BirthDay: DateTime: {18.08.2009 07:37:06}
-> Name: String: "Name949c7c83-c77b-434f-a8fe-e0aa73f81fbe"
-> Spouse: Person: null

More Information

http://blog.ploeh.dk/2009/08/17/OmittingOnlyCertainPropertiesWithAutoFixture.aspx

Perform Action

var mc = fixture.CreateAnonymous<MyClass>();
var mvm = fixture.Build<MyViewModel>()
    .Do(x => x.AvailableItems.Add(mc))
    .With(x => x.SelectedItem, mc)
    .CreateAnonymous();

Sample Result

MyViewModel:
-> AvailableItems: ICollection<MyClass>
--> MyClass (mc)
-> SelectedItem: MyClass (mc)

More Information

http://blog.ploeh.dk/2009/08/25/DoRedux.aspx

Customize Type

var mc = fixture.CreateAnonymous<MyClass>();
fixture.Customize<MyViewModel>(ob => ob
    .Do(x => x.AvailableItems.Add(mc))
    .With(x => x.SelectedItem, mc));
var mvm = fixture.CreateAnonymous<MyViewModel>();

Sample Result

MyViewModel:
-> AvailableItems: ICollection<MyClass>
--> MyClass (mc)
-> SelectedItem: MyClass (mc)

More Information

http://blog.ploeh.dk/2009/09/22/CustomizingATypesBuilderWithAutoFixture.aspx

Auto-Mocking with Moq

Add a reference to assembly Ploeh.AutoFixture.AutoMoq that includes an auto-mocking extension that uses Moq for Test Doubles.
fixture.Customize(new AutoMoqCustomization());
var result = fixture.CreateAnonymous<IInterface>();

Sample Result

A mocked instance of a type assignable from IInterface.

More Information

http://blog.ploeh.dk/2010/08/19/AutoFixtureAsAnAutomockingContainer.aspx

Last edited Jan 2, 2012 at 12:30 PM by baxevanis, version 16

Comments

LeonSuarez Jan 14, 2011 at 8:12 PM 
there is any way to limit the lenght for the string generated values? Thanks.