def notPresent = providerWithNoValue()
        def usesDefaultValue = notPresent.orElse(supplier1).orElse(supplier2).orElse(supplier3)
        usesDefaultValue.present
        usesDefaultValue.get() == someValue()
    }

    def "can unpack state and recreate instance when provider has no value"() {
        given:
        def provider = providerWithNoValue()

        expect:

            assert false: "never called"
        }))

        expect:
        propertyWithBadValue.toString() == "property(java.lang.String, map(java.lang.String provider(?) check-type()))"
        providerWithNoValue().toString() == "property(java.lang.String, undefined)"
    }

    def "can set null value to discard value"() {
        given:
        def property = property()
        property.set(someValue())

import org.gradle.internal.state.ManagedFactory

import java.util.concurrent.atomic.AtomicInteger


class WithSideEffectProviderTest extends ProviderSpec<Integer> {

    @Override
    Provider providerWithNoValue() {
        return WithSideEffectProvider.of(Providers.notDefined(), Stub(ValueSupplier.SideEffect))
    }

    @Override
    Provider<Integer> providerWithValue(Integer value) {