import org.bouncycastle.cms.SignerInformation;

public class SignerInformationConsumer {
    public String interact(SignerInformation si) {
        return si.getDigestAlgOID();
    }
}

import org.bouncycastle.cms.SignerInformation
import spock.lang.Shared
import spock.lang.Specification

class SignerInformationConsumerTest extends Specification {

    @Shared
    SignerInformation si = Mock()

    def "should return valid array"() {
        given:
            SignerInformationConsumer test = new SignerInformationConsumer()
            si.digestAlgOID >> "aaa"
        when:
            String digest = test.interact(si)
        then:
            digest == "aaa"
    }
}

plugins {
    id 'java'
}

group 'test'
version '1.0-SNAPSHOT'

sourceCompatibility = 1.8

repositories {
    mavenCentral()
}

dependencies {
    testCompile group: 'org.spockframework', name: 'spock-core', version: '1.1-groovy-2.4'
    testCompile 'net.bytebuddy:byte-buddy:1.8.0'
    compile group: 'org.bouncycastle', name: 'bcpkix-jdk15on', version: '1.60'
}