given:
        def property = property()
        property.set(someValue())
        property.set((Iterable) null)

        expect:
        !property.present
        property.getOrNull() == null
        property.getOrElse(someValue()) == someValue()
        property.getOrElse(null) == null
    }

    def "can set null value to remove any added values"() {
        property.add("abc")

        given:
        property.set(notDefined())
        and:
        property.put('k1', 'v1')
        property.put('k2', Providers.of('v2'))
        property.putAll(['k3': 'v3'])
        property.putAll(Providers.of(['k4': 'v4']))

        expect:
        !property.present
        property.getOrNull() == null
        property.getOrElse(['kk': 'vv']) == ['kk': 'vv']

        when:
        property.get()
        then:

        <profile>
            <id>profile-2</id>
            <activation>
                <property>
                    <name>${customPropertyName}</name>
                    <value>BLUE</value>
                </property>
            </activation>
            <properties>
                <prop2>myproperty2</prop2>
            </properties>
        </profile>
    </profiles>
</project>
"""

        property.get() == someValue()

        property.set(someOtherValue())
        property.present
        property.get() == someOtherValue()
    }

    def "can use null convention value"() {
        def property = propertyWithNoValue()
        assert property.getOrNull() != someValue()

        expect:
        nullConvention(property)

        !property.present
        property.getOrNull() == null

    }

    private static boolean isNameProperty(PropertyMetadata property) {
        // Property is read only, called "name", has type String and getter is abstract
        return property.isReadOnly() && "name".equals(property.getName()) && property.getType() == String.class && property.getMainGetter().isAbstract();
    }

    private static boolean hasPropertyType(PropertyMetadata property) {

)

// DEVPROPGUID specifies a property category.
type DEVPROPGUID GUID

// DEVPROPID uniquely identifies the property within the property category.
type DEVPROPID uint32

const DEVPROPID_FIRST_USABLE DEVPROPID = 2

// DEVPROPKEY represents a device property key for a device property in the
// unified device property model.
type DEVPROPKEY struct {
	FmtID DEVPROPGUID
	PID   DEVPROPID

    <profiles>
        <profile>
            <id>profile-1</id>
            <activation>
                <property>
                    <name>!someProperty</name>
                </property>
            </activation>
            <properties>
                <some.group>group-one</some.group>
                <some.artifact>artifact-one</some.artifact>
                <some.version>version-one</some.version>

<2> Reads the value from the project extra property we created — note the `project.` qualifier on `extra[...]`, otherwise Gradle will assume we want to read an extra property from the _task_

// === `Property`, `Provider` and `NamedDomainObjectProvider`


[[kotdsl:assignment]]
== Kotlin lazy property assignment

`testLogging` — default: _not set_::
This property represents a set of options that control which test events are logged and at what level. You can also configure other logging behavior via this property. See link:{javadocPath}/org/gradle/api/tasks/testing/logging/TestLoggingContainer.html[TestLoggingContainer] for more detail.

`dryRun` — default: false::

        failureDescriptionContains("- Type 'Consumer' property 'counter' doesn't have a configured value.")
        failureDescriptionContains("Reason: This property isn't marked as optional and no value has been configured.")
    }

    def "injection by name does not fail validation if service is not found but property marked as @Optional"() {
        given:
        serviceImplementation()