使用 Gradle 和 Groovy/Spock 测试 Java 6 库或应用程序

Question

I have a Java library, built by Gradle 2.4, that will be used by some apps that are Java 6, some that are Java 7, some that are Java 8, and some that are Groovy 2.x. As such, to be as backwards-compatible as possible, I am writing the lib to have both a sourceCompatibility as well as a targetCompatibility of 1.6 :

build.gradle
============
apply plugin: 'java'
apply plugin: 'groovy'

sourceCompatibility = '1.6'
targetCompatibility = '1.6'

repositories {
    mavenCentral()
    jcenter()
}

dependencies {
    compile (
        'org.slf4j:slf4j-api:1.7.12'
    )

    testCompile (
        'org.codehaus.groovy:groovy-all:2.4.6'
        ,'org.spockframework:spock-core:1.0-groovy-2.4'
    )
}

However, there's no reason why I shouldn't be able to write my unit tests in Groovy/Spock. So long as Groovy is not part of the main/compile/runtime classpath, then I should be free to write my tests in any JVM language I please! And I choose Groovy/Spock!

The problem is, I've never done something like this before. I think I need to add Groovy-All and Spock to the testCompile classpath, however I'm not sure if I need to apply the Groovy plugin or not, as well as any other configs.

Again:

• The main compile/runtime classpath must be Groovy-free and must be compatible with Java 1.6
• The test compile/runtime classpath can include anything I like

Any ideas as to what specific changes I need to make above?

Answer 1

If you want Gradle to compile any Groovy, be that main source or just test source, you will want to apply the groovy gradle plugin. That said, as long as you are not building a fat jar (that is, a JAR library that includes dependent libraries within itself so it can run as a standalone application), then you should not have any ties to Groovy on the runtime classpath. You are correct that you will want to add Spock/Groovy to your testCompile dependencies, and as long as you keep them scoped to testCompile, even creating a fat JAR shouldn't include them in your main compile classpath, in the final built artifact, or required to be on the classpath at runtime.

On a related note, in Gradle you also have access to modify the configurations of any and all dependencies. Have a look at the Gradle Dependency Management docs for some more information on that.