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September 1, 2015

Spocklight: Auto Cleanup Resources

Spcok has a lot of nice extensions we can use in our specifications. The AutoCleanup extension makes sure the close() method of an object is called each time a feature method is finished. We could invoke the close() method also from the cleanup method in our specification, but with the @AutoCleanup annotation it is easier and immediately shows our intention. If the object we apply the annotation to doesn't have a close() method to invoke we can specify the method name as the value for the annotation. Finally we can set the attribute quiet to true if we don't want to see any exceptions that are raised when the close() method (or custom method name, that is specified) is invoked.

In the following example code we have a specification that is testing the WatchService implementation. The implementation also implements the Closeable interface, which means we can use the close() method to cleanup the object properly. We also have a custom class WorkDir with a delete() method that needs to be invoked.

package com.mrhaki.spock

import spock.lang.AutoCleanup
import spock.lang.Specification

import java.nio.file.FileSystems
import java.nio.file.Files
import java.nio.file.Path
import java.nio.file.Paths
import java.nio.file.WatchKey
import java.nio.file.WatchService
import java.util.concurrent.TimeUnit

import static java.nio.file.StandardWatchEventKinds.ENTRY_CREATE

class WatchSpec extends Specification {

    // Use close() method of WatchService
    // when feature method is done.
    @AutoCleanup
    private WatchService watchService

    // Use delete() method of WorkDir class
    // when feature method is done.
    // If the quiet attribute is true, then
    // exceptions from the delete() method are
    // not shown, otherwise exceptions are reported.
    @AutoCleanup(value = 'delete', quiet = true)
    private WorkDir testPath = new WorkDir('test-dir')

    def setup() {
        // Get new watch service.
        watchService = FileSystems.default.newWatchService()

        // Register for events when a new file is created
        // in the testPath directory.
        testPath.path.register(watchService, ENTRY_CREATE)
    }

    def "get notification when file is created"() {
        given:
        final Path testFile = testPath.path.resolve('test-file')
        testFile << 'sample'

        and:
        final WatchKey watchKey = watchService.poll(10, TimeUnit.SECONDS)

        when:
        final events = watchKey.pollEvents()

        then:
        events.size() == 1
        events[0].kind() == ENTRY_CREATE

        cleanup:
        Files.delete(testFile)
    }

}

class WorkDir {

    private final Path path

    WorkDir(final String dir) {
        path = Paths.get(dir)
        Files.createDirectories(path)
    }

    Path getPath() {
        path
    }

    void delete() {
        Files.deleteIfExists(path)
    }

}

Written with Spock 1.0-groovy-2.4.