AutoFixture Create An Instance from An Interface Issue

Question

My issue is, cannot create auto generated instance from the interface.

Here is my example:

public class SomeClass {
    public string TestName { get; set; }
}

// And then I call like this
var obj = new Fixture().Create<SomeClass>();

Concrete class is generated automatically and it's properties like this:

Console.WriteLine(obj.TestName);
// Output: TestNameb7c3f872-9286-419f-bb0a-c4b0194b6bc8

But I have an interface like below:

public interface ISomeInterface 
{
    string TestName { get; set; }
}

// And  then I call like this
var obj = new Fixture().Create<ISomeInterface >();

It is generated but it's properties is not set.

Console.WriteLine(obj.TestName);
// Output: null

How can I create an instance from the interface like the concrete class?

May be a duplicate of https://stackoverflow.com/questions/10208648/autofixture-and-interfaces — Matthew Watson, Oct 23 '20 at 13:27

score 2 · Accepted Answer · answered Oct 23 '20 at 13:39

2

Agree with Mathew Watson comment, this question might already be answered in the mentioned question.

Just wanted to share my version which is slightly different from those answer from 2012 ;)

public interface ISomeInterface
{
    string TestName { get; set; }
}

public class SomeClass : ISomeInterface
{
    public string TestName { get; set; }
}

public class Test
{
    [Fact]
    public void Do()
    {
        var fixture = new Fixture();
        fixture.Customize<ISomeInterface>(x => x.FromFactory(() => new SomeClass()));
        var result = fixture.Create<ISomeInterface>();
        Console.Out.WriteLine("result = {0}", result.TestName);
        // output:
        // result = TestName2c7e6902-d959-46ce-a79f-bf933bcb5b7f
    }
}

Of course, AutoMoq or AutoNSubstitute are the options to consider.

answered Oct 23 '20 at 13:39

Serhii Shushliapin

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Do I must write a class what derived from my interface? I do not want to do it. – hakanaltindis Oct 24 '20 at 17:43
1

Then use AutoMoq or AutoNsubstitute – Serhii Shushliapin Oct 24 '20 at 17:50
Thanks, I missed out about auto moq before. `new Fixture().Customize(new AutoMoqCustomization { ConfigureMembers = true })` this code block solved my issue. Especially, `ConfigureMember = true`. – hakanaltindis Oct 26 '20 at 05:38

AutoFixture Create An Instance from An Interface Issue

1 Answers1