failure.assertHasCause("Cannot convert string value 'unsupportedValue' to an enum value of type 'SampleTask\$TestEnum' (valid case insensitive values: OPT_1, OPT_2, OPT_3)")
    }

    def "decent error for invalid enum list value"() {
        given:
        buildFile << """
            task someTask(type: SampleTask)

            ${taskWithSingleOption('List<TestEnum>')}
        """

        when:

            import org.gradle.api.tasks.TaskAction;
            import org.gradle.api.tasks.options.Option;

            import java.util.List;
            
            public class SampleTask extends DefaultTask {
                private $optionType myProp;
                
                @Option(option = "myProp", description = "Configures command line option 'myProp'.")

            "unexpected '${javaExecutable.get().asFile.absolutePath} -version' output"
        }
    }
}

tasks.register<TaskThatRequiresJavaExecutable>("sampleTask")
val TaskContainer.sampleTask
    get() = named<TaskThatRequiresJavaExecutable>("sampleTask")


abstract class TaskThatRequiresJavaHome : DefaultTask() {

    @get:Internal
    abstract val javaHome: DirectoryProperty

    @get:Inject

        }
        assert outputBytes.toString("UTF-8").contains("version \"11"):
            "unexpected '${javaExecutable.get().asFile.absolutePath} -version' output"
    }
}

tasks.register("sampleTask", TaskThatRequiresJavaExecutable)


abstract class TaskThatRequiresJavaHome extends DefaultTask {

    @Internal
    abstract DirectoryProperty getJavaHome()

    @Inject

executable: gradle

.build.gradle.kts
[source,kotlin]
----
import org.gradle.api.Plugin
import org.gradle.api.Project

abstract class SamplePlugin : Plugin<Project> {
    override fun apply(project: Project) {
        project.tasks.create("SampleTask") {
            println("Hello world!")
        }
    }
}
----

== Script plugin

Many plugins start as a script plugin coded in a build script.

        expect:
        changesBetween(
            impl(SimpleTask), [impl(TestAction, previousHash)],
            impl(SimpleTask), [impl(TestAction)]
        ) == ["One or more additional actions for task ':test' have changed."]
    }

    def "not up-to-date when action is added"() {
        expect:
        changesBetween(
            impl(SimpleTask), [],
            impl(SimpleTask), [impl(TestAction)]

            }

            def continuousExecutionGate = gradle.services.get(DeploymentRegistryInternal).executionGate
            BuildGateKeeperStarter.start(continuousExecutionGate)

            class SimpleTask extends DefaultTask {
                @InputFile
                File inputFile = project.file("input.txt")

                @OutputFile
                File outputFile = new File(project.buildDir, "output.txt")