def "supplies no installations for non-existing directory"(boolean useProperty) {
        assert mavenHome.delete()

        given:
        def supplier = useProperty ? createSupplier(mavenHome.getCanonicalPath(), null) : createSupplier(null, userHome)

        when:
        def directories = supplier.get()

        then:
        directories.isEmpty()

        where:
        useProperty << [true, false]
    }

class WindowsInstallationSupplierTest extends Specification {

    def registry = Mock(WindowsRegistry)

    def "no detection for non-windows os"() {
        given:
        def supplier = createSupplier(OperatingSystem.MAC_OS)

        when:
        supplier.get()

        then:
        0 * registry._
    }

    def "finds openjdk homes"() {
        given:

        given:
        def supplier = createSupplier([] as Set)

        when:
        def directories = supplier.get()

        then:
        directories.isEmpty()
    }

    def "supplies single installations for single candidate"() {
        def jdk = temporaryFolder.createDir("11.0.6.hs-adpt")
        given:
        def supplier = createSupplier([jdk] as Set)

        when: