Over a million developers have joined DZone.

Spocklight: Capture and Assert System Output

· Java Zone

Navigate the Maze of the End-User Experience and pick up this APM Essential guide, brought to you in partnership with CA Technologies

Spock supports JUnit rules out of the box. We simply add a rule with the @Rule annotation to our Spock specification and the rule can be used just like in a JUnit test. The Spring Boot project contains a JUnit rule OutputCapture to capture the output of System.out and System.err.

In the following example specification we apply the OutputCapture rule and use it in two feature methods:

package com.mrhaki.spock

@Grab('org.spockframework:spock-core:0.7-groovy-2.0')
import spock.lang.*

@Grab('org.springframework.boot:spring-boot:1.2.1.RELEASE')
import org.springframework.boot.test.OutputCapture

class CaptureOutputSpec extends Specification {

    @org.junit.Rule
    OutputCapture capture = new OutputCapture()


    def "capture output print method"() {
        when:
        print 'Groovy rocks'

        then:
        capture.toString() == 'Groovy rocks'
    }

    def "banner text must contain given messagen and fixed header"() {
        given:
        final Banner banner = new Banner(message: 'Spock is gr8!')

        when:
        banner.print()

        then:
        final List lines = capture.toString().tokenize(System.properties['line.separator'])
        lines.first() == '*** Message ***'
        lines.last()  == ' Spock is gr8! '
    }

}


/**
 * Class under test. The print method
 * uses println statements to display
 * some message on the console.
 */
class Banner {

    String message 

    void print() {
        println ' Message '.center(15, '*')
        println message.center(15)
    }

}

Written with Spock-0.7-groovy-2.0.

Thrive in the application economy with an APM model that is strategic. Be E.P.I.C. with CA APM.  Brought to you in partnership with CA Technologies.

Topics:

Published at DZone with permission of Hubert Klein Ikkink, DZone MVB. See the original article here.

Opinions expressed by DZone contributors are their own.

The best of DZone straight to your inbox.

SEE AN EXAMPLE
Please provide a valid email address.

Thanks for subscribing!

Awesome! Check your inbox to verify your email so you can start receiving the latest in tech news and resources.
Subscribe

{{ parent.title || parent.header.title}}

{{ parent.tldr }}

{{ parent.urlSource.name }}