}

    def "fails when property has multiple producers attached"() {
        def owner1 = owner()
        owner1.modelIdentityDisplayName >> displayName("<owner 1>")
        def owner2 = owner()
        owner2.modelIdentityDisplayName >> displayName("<owner 2>")

        given:
        def property = propertyWithNoValue()
        property.attachProducer(owner1)

        when: