public void WhenExportProvidedUpFront_ThenEvaluatesTrue()
{
var catalog = new TypeCatalog(typeof(Foo), typeof(Bar));
var container = new CompositionContainer(catalog);
var compositionService = new CompositionContainerService(container);
var binding = new Binding <IFoo>(compositionService, "Foo");
var result = binding.Evaluate();
Assert.IsTrue(result);
}
public void WhenExportProvidedLater_ThenEvaluatesTrue()
{
// Note catalog now doesn't contain the IBar dependency.
var catalog = new TypeCatalog(typeof(Foo));
var container = new CompositionContainer(catalog);
var compositionService = new CompositionContainerService(container);
//// CompositionInfoTextFormatter.Write(new CompositionInfo(catalog, container), Console.Out);
var binding = new Binding <IFoo>(compositionService, "Foo");
var result = binding.Evaluate();
// As appropriate, this now evaluates to false.
Assert.IsFalse(result);
// To re-assure this is the proper behavior, the unresolved import causes the
// component to be unavailable via a plain query:
var lazyValue = container.GetExports <IFoo, IComponentMetadata>()
.FirstOrDefault(component => component.Metadata.Id == "Foo");
Assert.IsNull(lazyValue);
// Here we provide the missing export.
container.ComposeExportedValue <IBar>(new Bar());
// CompositionInfoTextFormatter.Write(new CompositionInfo(catalog, container), Console.Out);
// Note how now the component becomes available via query, as
// the dependency is now satisfied.
lazyValue = container.GetExports <IFoo, IComponentMetadata>()
.FirstOrDefault(component => component.Metadata.Id == "Foo");
Assert.IsNotNull(lazyValue);
// And re-evaluate, which should now locate the component as
// its imports are satisfied.
result = binding.Evaluate();
// But this fails :(
Assert.IsTrue(result);
}
