toolchainConfiguration.getIntelliJdkDirectory() >> candidates
    }

    def "supplies no installations for empty directory"() {
        when:
        def directories = supplier.get()

        then:
        directories.isEmpty()
    }

    def "supplies no installations for non-existing directory"() {
        given:
        assert candidates.deleteDir()

        when:

                }
            }
        """
    }

    AbstractIntegrationSpec withAutoDetection() {
        executer.withArgument("-Porg.gradle.java.installations.auto-detect=true")
        return this as AbstractIntegrationSpec
    }

    /**
     * Usage:
     * <pre>
     *     def jvm1 = Jvm.current()

public interface ToolchainConfiguration {
    String AUTO_DETECT = "org.gradle.java.installations.auto-detect";

    Collection<String> getJavaInstallationsFromEnvironment();
    void setJavaInstallationsFromEnvironment(Collection<String> installations);

    Collection<String> getInstallationsFromPaths();
    void setInstallationsFromPaths(Collection<String> installations);

    boolean isAutoDetectEnabled();

        when:
        def allArgs = executer.getAllArgs()

        then:
        allArgs.contains("-Porg.gradle.java.installations.auto-detect=false")
        allArgs.contains("-Porg.gradle.java.installations.auto-download=false")
    }

    def "toolchain detection can be enabled"() {
        when:
        executer.withToolchainDetectionEnabled()

    def "supplies no installations for absent property"() {
        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")

                        "see https://docs.gradle.org/current/userguide/toolchains.html#sub:download_repositories")
                .withTasks("compileJava", "-Porg.gradle.java.installations.auto-detect=false", "-Porg.gradle.java.installations.auto-download=true")
                .run()
    }

    private void assertJdkWasDownloaded(String implementation = null) {

        then:
        Map<NativeInstallationFixture, HelloWorldApp> installations = apps.collectEntries { name, app ->
            def installation = installation("build/install/${name}Main")
            [installation, app]
        }
        installations.every { installation, app ->
            installation.exec().out == app.englishOutput
        }

        and:

    def "supplies no installations for empty property"() {
        when:
        buildOptions.getJavaInstallationsFromEnvironment() >> []
        def directories = supplier.get()

        then:
        directories.isEmpty()
    }

    def "supplies single installations for single path"() {
        when:

        then:
        def previousJavaHome = getPrintedJavaHome(result)
        previousJavaHome.startsWith(jdkDir)

        and:
        jdkRepository.expectHead()

        when:
        result = version current withGradleUserHomeDir userHome withTasks 'run' withArguments '-Porg.gradle.java.installations.auto-download=true' run()

        then:

    def "supplies no installations for absent output"() {
        given:
        def supplier = new OsXInstallationSupplier(OperatingSystem.MAC_OS, osxJavaHomeCommand)
        osxJavaHomeCommand.findJavaHomes() >> []

        when:
        def directories = supplier.get()

        then:
        directories.isEmpty()
    }


    def "supplies no installations for wrong os"() {
        given: