Outputting the given, when, then, Extending Spock

Alex StaveleyJuly 17th, 2017Last Updated: July 17th, 2017

0 50 2 minutes read

Spock is a Java testing framework, created in 2008 by Peter Niederwieser a software engineer with GradleWare, which facilitates amongst other things BDD. Leveraging this
example, a story may be defined as:

<strong>Story:</strong> Returns go to stock
 
<strong>As a</strong> store owner
<strong>In order to</strong> keep track of stock
<strong>I want to</strong> add items back to stock when they're returned.
 
<strong>Scenario 1:</strong> Refunded items should be returned to stock
<strong>Given</strong> that a customer previously bought a black sweater from me
<strong>And</strong> I have three black sweaters in stock.
<strong>When</strong> he returns the black sweater for a refund
<strong>Then</strong> I should have four black sweaters in stock.
 
<strong>Scenario 2:</strong> Replaced items should be returned to stock
<strong>Given</strong> that a customer previously bought a blue garment from me
<strong>And</strong> I have two blue garments in stock
<strong>And</strong> three black garments in stock.
<strong>When</strong> he returns the blue garment for a replacement in black
<strong>Then</strong> I should have three blue garments in stock
<strong>And</strong> three black garments in stock.

Spock makes it possible to map tests very closely to scenario specifications using the same given, when, then format. In Spock we could implement the first scenario as:

class SampleSpec extends Specification{
    def "Scenario 1: Refunded items should be returned to stock"() {
        given: "that a customer previously bought a black sweater from me"
        // ... code 
        and: "I have three black sweaters in stock."
        // ... code
        when: "he returns the black sweater for a refund"
        // ... code
        then: "I should have four black sweaters in stock."
        // ... code
    }
}

What would be nice would be to ensure accurate mapping of test scenario requirements to test scenario implementation. We could get someway down this path if we could output the syntax of the
given, when, then from our test. Spock allows us to add this functionality through its extension framework.

So, let’s say our BA is really curious and wants more confidence from the developer that they stuck to the same given, when, then format and their code is in-sync. They want to get this information easily. Developer could provide this information by first defining this annotation

import java.lang.annotation.*
import org.spockframework.runtime.extension.ExtensionAnnotation
 
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.TYPE)
@ExtensionAnnotation(ReportExtension)
@interface LogScenarioDescription {}

Followed by this implementation:

import org.apache.log4j.Logger
import org.spockframework.runtime.AbstractRunListener
import org.spockframework.runtime.extension.AbstractAnnotationDrivenExtension
import org.spockframework.runtime.model.FeatureInfo
import org.spockframework.runtime.model.SpecInfo
 
 
class LogScenarioDescriptionExtension extends AbstractAnnotationDrivenExtension; {
    final static Logger logger = Logger.getLogger("scenarioLog." + ReportExtension.class);
 
    @Override
    void visitSpecAnnotation(Report annotation, SpecInfo spec) {
        spec.addListener(new AbstractRunListener() {
            @Override
            void afterFeature(FeatureInfo feature) {
                if (System.getEnv("logScenarios")) {
                    logger.info("***SCENARIO TEST:*** " + feature.name)
                    for (block in feature.blocks) {
                        logger.info(block.kind);
                        for (text in block.texts) {
                            logger.info(text)
                        }
                    }
                }
            }
        })
    }
}

This will then be applied to the test

@LogScenarioDescription
class SampleSpec extends Specification{
  //...

When the test is executed it gives the following output:

***SCENARIO TEST:*** Scenario 1: Refunded items should be returned to stock
GIVEN
that a customer previously bought a black sweater from me
AND
I have three black sweaters in stock.
WHEN
he returns the black sweater for a refund
THEN
I should have four black sweaters in stock.

output to a specific logfile for scenario logging by using the following log4j:

log4j.rootLogger=INFO, stdout
 
log4j.logger.scenarioLog.extension.custom=INFO, scenarioLog
 
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%m%n
 
log4j.appender.scenarioLog=org.apache.log4j.FileAppender
log4j.appender.scenarioLog.File=logs/scenario.log
log4j.appender.scenarioLog.layout=org.apache.log4j.PatternLayout
log4j.appender.scenarioLog.layout.ConversionPattern=%m%n

and now you have a logfile that your BA, QA can read! This helps foster an Agile culture of collaboration and ATDD where it possible to check that test scenarios implemented with those that were agreed.

Reference:

Outputting the given, when, then, Extending Spock from our JCG partner Alex Staveley at the Dublin’s Tech Blog blog.