I want configure Unity to resolve an interface, say `ITest`, to a struct, say `struct Test`. So far I have next:

```
<unity>
    <containers>
        <container>
            <types>
                <type
                    type="my.ITest, asm" 
                    mapTo="my.Test, asm">
                </type>
            </types>
        </container>
    </containers>
</unity>

```

but I'm getting next error:

```
Resolution of the dependency failed, type = "my.ITest", name = "(none)".
Exception occurred while: while resolving.
Exception is: InvalidOperationException - The type Test cannot be constructed. You must configure the container to supply this value.
At the time of the exception, the container was:    
Resolving my.Test,(none) (mapped from my.ITest,(none))

```

Why?