public void ReferenceSetup_WithFirstModelledThenPreexisting_ThrowsInvalidOperationException()
{
// Arrange
var mapping = new ComponentMapping <EventHubNamespace>(null);
// Act & Assert
var ex = Assert.Throws <InvalidOperationException>(() => mapping
.WithModelledHierarchyReference(eh => eh.ResourceGroup, ModelledReferenceDirection.Child)
.WithPreexistingHierarchyReference("Namespace"));
Assert.Equal("Can only configure a single reference where the class is the child.", ex.Message);
}