public void PropagateChildErrors_WithInvalidChildren_ParentHasError() { var error = "Child records are invalid"; var validItem = new ChildVM(); var invalidItem = new ChildVM(); var childDescriptor = CreateChildDescriptor(b => b.CheckViewModel(args => { if (args.Target == invalidItem) { args.AddError("Item error"); } })); ParentVM vm = CreateParent(b => b.PropagateChildErrors(error), childDescriptor); vm.Children.Add(validItem); ValidationAssert.IsValid(vm.ValidationResult); vm.Children.Add(invalidItem); var actualParentValidationState = vm.GetValidationResult(ValidationResultScope.Self); ValidationAssert.ErrorMessages(actualParentValidationState, error); }