public File getInputDirectory() {
                    return new File("input");
                }

                @InputFile
                public File getInputFile() {
                    return new File("input.txt");
                }

                @InputFiles
                public Set<File> getInputFiles() {
                    return Collections.emptySet();
                }

                @Input

import org.gradle.api.tasks.CompileClasspath;
import org.gradle.api.tasks.Console;
import org.gradle.api.tasks.IgnoreEmptyDirectories;
import org.gradle.api.tasks.Input;
import org.gradle.api.tasks.InputFiles;
import org.gradle.api.tasks.Internal;
import org.gradle.api.tasks.Nested;
import org.gradle.api.tasks.Optional;
import org.gradle.api.tasks.OutputDirectory;
import org.gradle.api.tasks.PathSensitive;

import org.gradle.api.file.ConfigurableFileCollection
import org.gradle.api.file.Directory
import org.gradle.api.tasks.GroovySourceDirectorySet
import org.gradle.api.tasks.InputDirectory
import org.gradle.api.tasks.InputFiles
import org.gradle.api.tasks.PathSensitive
import org.gradle.api.tasks.PathSensitivity
import org.gradle.api.tasks.SourceSet
import org.gradle.api.tasks.SourceSetContainer
import org.gradle.api.tasks.TaskProvider

                    outputFile.text = "produced"
                }
            }

            task consumer {
                def inputFile = file("output.txt")
                inputs.files(inputFile)
                doLast {
                    println "Hello " + inputFile.text
                }
            }
        """

        when:
        runAndFail("producer", "consumer")
        then:

    }

    def "cacheability for a task with no sources is UNKNOWN"() {
        buildFile """
            @CacheableTask
            class NoSources extends UnspecifiedCacheabilityTask {
                @InputFiles
                @SkipWhenEmpty
                FileCollection empty = project.layout.files()
            }

            task noSources(type: NoSources)
        """
        when:

import org.gradle.api.tasks.Classpath
import org.gradle.api.tasks.IgnoreEmptyDirectories
import org.gradle.api.tasks.Input
import org.gradle.api.tasks.InputDirectory
import org.gradle.api.tasks.InputFiles
import org.gradle.api.tasks.Internal
import org.gradle.api.tasks.OutputDirectory
import org.gradle.api.tasks.PathSensitive
import org.gradle.api.tasks.PathSensitivity
import org.gradle.api.tasks.TaskAction

                        new File(outputFile, i.toString()).mkdirs()
                    }
                }
            }

            abstract class ConsumerTask extends DefaultTask {
                @InputFiles
                abstract ConfigurableFileCollection getMyInputs()

                @OutputFile
                abstract RegularFileProperty getOutputFile()

                @TaskAction

            }

            tasks.register("checkDeps", CheckDeps) {
                input.from(configurations.runtimeClasspath)
            }

            class CheckDeps extends DefaultTask {
                @InputFiles
                final ConfigurableFileCollection input = project.objects.fileCollection()

                @TaskAction
                void doSomething() {
                    println input.files.name

                    on { displayNameOf(inputFile) } doReturn "displayNameOf(inputFile)"
                },
                ConfigurationCacheFingerprint.InputFile(
                    inputFile,
                    originalFileHash
                )
            ),
            equalTo("file 'displayNameOf(inputFile)' has been replaced by a directory")

                @InputFile inputFile
                @OutputFile outputFile

                @TaskAction copy() {
                    outputFile.parentFile.mkdirs()
                    outputFile.text = inputFile.text
                }
            }
            task customTask(type: NonCacheableTask) {
                inputFile = file("input.txt")