Freeze enum value in AutoFixture

Question

We have an enum:

enum Letters
{
    A,
    B,
    C,
    D,
    E        
}

When I try:

var frozenLetter = fixture.Freeze(Letters.D);

Strangely, frozenLetter == A.

var letter = fixture.Create<Letters>();
var anotherLetter = fixture.Create<Letters>();

Letter and anotherLetter both equal A, so the Letters type has been frozen, but to the first constant in the enum rather than the one specified.

Is there a way to freeze an enum to the constant I wish?

Galegalea

I might be missing something, but what does the Freeze method do? – Lacework

It "freezes" the type so that it always returns the same instance whenever an instance of that type is requested. See AutoFixture Freeze by Mark Seeman, AutoFixture's author. – Galegalea

Hm, looks like enums are not supported by AutoFixture. As a workaround you could declare a constant (private const Letters constLetter = Letters.D;) at the top of your class and use that instead of creating enums with AutoFixture. – Columbarium

They are now: see EnumGenerator.cs. That would be a simple work-around but an instance of Letters is created indirectly a nested value of other types. – Galegalea

@Pierre-LucPineault Please note that the very resource you link to explicitly states that the issue was fixed in July 2010! – Tollmann

Answer 1

Freeze Inject and Register are slightly different.

Use Inject for the described behavior, as the following test demonstrates:

[Fact]
public void Test()
{
    var fixture = new Fixture();

    var expected = Letters.D;
    fixture.Inject(expected);

    var letter = fixture.Create<Letters>();
    var anotherLetter = fixture.Create<Letters>();

    Assert.Equal(expected, letter);
    Assert.Equal(expected, anotherLetter);
}

The problem with the question's sample code is that the parameter (seed) isn't used as the frozen value.

Sotted

Aha, classic mistake there. Thanks for the clear explanation. – Galegalea