Indicate Fake name (if defined) in failing assertions

When working with a collection of Fakes it’s sometimes difficult to determine which one of them violated expectations.

I came across two cases when this becomes a problem:

1. Verifing expectations in a loop:

void TestMethod(IList<IInterface> dependencies)
{
	dependencies[1].Method1();
}

[Test]
public void TestCollection()
{
	var fakes = A.CollectionOfFake<IInterface>(3);

	TestMethod(fakes);

	foreach (var fake in fakes)
	{
		A.CallTo(() => fake.Method1())
			.MustNotHaveHappened();
	}
}

This causes:

FakeItEasy.ExpectationException : 

  Assertion failed for the following call:
    Tests.IInterface.Method1()
  Expected to find it never but found it once among the calls:
    1: Tests.IInterface.Method1()

1. Using strict Fakes:

void TestMethod(IList<IInterface> dependencies)
{
	foreach (var dependency in dependencies)
		dependency.Method1();
}

[Test]
public void Strict()
{
	var fakes = A.CollectionOfFake<IInterface>(3, o => o.Strict());

	TestMethod(fakes);
}

which results in an error:

FakeItEasy.ExpectationException : Call to unconfigured method of strict fake: Tests.IInterface.Method1().

Named Fakes seem to be an intuitive and convenient way of solving this problem, but unfortunately assigned names are only displayed if a named Fake is used as an argument of a call, so at the moment they cannot help in situations described above.

It would be very helpful if Fake names were also included in error messages, e.g. with Fakes from previous examples named Dependency1 and Dependency0:

FakeItEasy.ExpectationException : 

  Assertion failed for the following call on Dependency1:
    Tests.IInterface.Method1()
  Expected to find it never but found it once among the calls:
    1: Tests.IInterface.Method1()

and

FakeItEasy.ExpectationException : Call to unconfigured method of strict fake Dependency0: Tests.IInterface.Method1().

A new overload for A.CollectionOfFake could also simplify assigning a unique name to each Fake:

var fakes = A.CollectionOfFake<IInterface>(3, (o, i) => o.Named($"Fake{i}"));

[thomaslevesque]

Hi @PiotrKlecha,

I agree that indicating the fake name in ordered assertion messages would be useful, however I don’t think the suggested format is appropriate. Currently the message indicates on which interface the expected call must happen. If you replace the whole thing with the fake name, you lose that information.

Consider this:

public interface IFoo
{
    int Get();
}

public interface IBar
{
    int Get();
}

public class FooBar : IFoo, IBar
{
    public virtual int Get() => 42;
}

FooBar fake = A.Fake<FooBar>();

//  Assertion failed for the following call:
//    UserQuery+IFoo.Get()
A.CallTo(() => ((IFoo)fake).Get()).MustHaveHappened();

//  Assertion failed for the following call:
//    UserQuery+IBar.Get()
A.CallTo(() => ((IBar)fake).Get()).MustHaveHappened();

This is a silly example, of course, but I think it illustrates the point.

Maybe the calls should be shown like this instead:

Tests.IInterface.Method1() on Dependency1

[PiotrKlecha]

@blairconrad I’d like to finish #1838 first but then perhaps I could also take a look at this one.