abstract ConfigurableFileCollection getOutputFiles()

                @Inject
                abstract ProjectLayout getLayout()

                @TaskAction
                void doStuff() {
                    layout.buildDirectory.file("dir1/output1.txt").get().asFile.text = "first"
                    layout.buildDirectory.file("dir2/output2.txt").get().asFile.text = "second"
                }

 */

package org.gradle.testfixtures

import org.gradle.api.DefaultTask
import org.gradle.api.tasks.TaskAction


class CustomTask extends DefaultTask {
    String property

    @TaskAction
    def doStuff() {
        property = 'some value'
    }

try {
    buildscript.classLoader.loadClass('BuildSrcClass')
    assert false: 'should fail'
} catch (ClassNotFoundException e) {
    // expected
}
"""
        buildFile << 'task doStuff'

        when:
        run('doStuff')

        then:
        output.contains('quiet message')
        errorOutput.contains('error message')
    }

    private TestFile createBuildSrc() {

                abstract DirectoryProperty getLocalStateDirectory()
                @OutputFile
                abstract RegularFileProperty getOutputFile()

                @TaskAction
                void doStuff() {
                    def localStateDir = localStateDirectory.get().asFile
                    localStateDir.mkdirs()
                    new File(localStateDir, "localState.txt").text = "localState"

                @Input
                public FileTree getFileTree() {
                    return getProject().files().getAsFileTree();
                }

                @TaskAction
                public void doStuff() { }
            }
        """

        when:
        executer.withArgument("-Dorg.gradle.internal.max.validation.errors=7")

        then:
        assertValidationFailsWith([

        succeeds("build")
        executedAndNotSkipped ":compileJava", ":build"
        vfsLogs.getRetainedFilesInCurrentBuild() >= numberOfFilesInVfs

        when:
        sourceFile.text = "class Thing { public void doStuff() {} }"

        then:
        buildTriggeredAndSucceeded()
        vfsLogs.getRetainedFilesSinceLastBuild() >= numberOfFilesInVfs - 1
        vfsLogs.getRetainedFilesInCurrentBuild() >= numberOfFilesInVfs

                @Input
                public FileTree getFileTree() {
                    return getProject().files().getAsFileTree();
                }

                @TaskAction
                public void doStuff() { }
            }
        """

        expect:
        executer.withArgument("-Dorg.gradle.internal.max.validation.errors=10")
        assertValidationFailsWith([

        TaskWithMultiParamAction              | "Cannot use @TaskAction annotation on method TaskWithMultiParamAction.doStuff() as this method takes multiple parameters."
        TaskWithSingleParamAction             | "Cannot use @TaskAction annotation on method TaskWithSingleParamAction.doStuff() because int is not a valid parameter to an action method."

    }

    def canCreateAndExecuteACustomTask() {
        when:
        def project = buildProject()
        def task = project.task('custom', type: CustomTask)
        task.doStuff()

        then:
        task.property == 'some value'
    }

    @LeaksFileHandles("script jar is held open")
    def canApplyABuildScript() {
        when:
        def project = buildProject()

Make sure the correct language is added to the class name: `language-kotlin`, `language-groovy`, or `language-java`:

```java
/**
 * <pre><code class="language-kotlin">
 * project.ext.prop1 = "foo"
 * task doStuff {
 *     ext.prop2 = "bar"
 * }
 * subprojects { ext.${prop3} = false }
 * </code></pre>
 */
```