Guide for Testing Gradle Scripts

Question

What are the best practices for testing Gradle Scripts?

I currently unit test my ant scripts with antunit, but I'm looking to migrate to Gradle. I can only find articles on testing Java code from Gradle or Groovy, but nothing on testing the Gradle tasks that I create or testing Groovy in general. Is there an equivalent of antunit for Gradle? Has anyone played with a BDD framework (like cucumber) to test Gradle scripts?

For instance, I currently have the following Ant Target

<target name="dist-bin" depends="build" description="creates a zip distribution of the current build">
    <zip destfile="build/TIBant-bin.zip">
        <zipfileset dir="src/ant" includes="**" />
        <zipfileset dir="test" includes="**" prefix="test" />
        <zipfileset dir="build" includes="TIBant.jar" />
        <zipfileset dir="build" includes="TIBant-*.html" />
        <zipfileset dir="build/examples/XMLtoProperties"
                    includes="XMLtoProperties.html"
                    prefix="examples/XMLtoProperties" />
        <zipfileset dir="lib" includes="**" prefix="lib" />
        <zipfileset dir="src/xslt" includes="**" excludes="test/**,userguide.xslt" prefix="lib/xslt" />
        <zipfileset dir="." includes="copyright.html,LICENSE.txt" />
        <zipfileset dir="examples"
                    includes="**"
                    excludes="**/build/**,**/config/default.properties"
                    prefix="examples" />
    </zip>
</target>

As you can imagine, it's pretty easy to break this when refactoring the project, so I have the following antunit test to check it.

<target name="test-dist-bin">
    <delete file="build/TIBant-bin.zip" />
    <au:assertFalse message="Bin dist still present">
        <available file="build/TIBant-bin.zip" />
    </au:assertFalse>
    <antcall target="dist-bin" />
    <au:assertTrue message="Bin dist not created">
        <available file="build/TIBant-bin.zip" />
    </au:assertTrue>
    <delete dir="build/testBinDist" />
    <au:assertFalse message="TestBinDist still present">
        <available file="build/testBinDist" />
    </au:assertFalse>
    <mkdir dir="build/testBinDist" />
    <unzip src="build/TIBant-bin.zip" dest="build/testBinDist" />
    <au:assertFalse message="config dir present">
        <available file="build/testBinDist/config/default.properties" />
    </au:assertFalse>
    <au:assertTrue message="Ant Macros missing">
        <available file="build/testBinDist/tibant.xml" />
    </au:assertTrue>
    <au:assertTrue message="Engine Stopper Jar missing">
        <available file="build/testBinDist/TIBant.jar" />
    </au:assertTrue>
    <au:assertTrue message="Ant-contrib-missing">
        <available file="build/testBinDist/lib/ant-contrib-1.0b3.jar" />
    </au:assertTrue>
    <au:assertTrue message="ant-unit missing">
        <available file="build/testBinDist/lib/ant-antunit-1.2.jar" />
    </au:assertTrue>
    <au:assertTrue message="Copyright missing">
        <available file="build/testBinDist/copyright.html" />
    </au:assertTrue>
    <au:assertTrue message="License missing">
        <available file="build/testBinDist/LICENSE.txt" />
    </au:assertTrue>
    <au:assertFalse message="Src present">
        <available file="build/testBinDist/src/java/org/windyroad/tibant/EngineStopper.jar" />
    </au:assertFalse>
    <au:assertTrue message="example missing">
        <available file="build/testBinDist/examples/SimpleProject/src/bw/example/Build/example.archive" />
    </au:assertTrue>
    <au:assertFalse message="example has build files">
        <available file="build/testBinDist/examples/SimpleProject/build/*" />
    </au:assertFalse>
    <au:assertFalse message="example has default config file">
        <available file="build/testBinDist/examples/SimpleProject/config/default.properties" />
    </au:assertFalse>
    <property name="doc.file"
              location="build/testBinDist/TIBant-User-Guide.html" />
    <au:assertTrue message="doc missing: ${doc.file}">
        <available file="${doc.file}" />
    </au:assertTrue>
    <au:assertTrue message="xslt missing">
        <available file="build/testBinDist/lib/xslt/configure-ear.xslt" />
    </au:assertTrue>
    <subant target="run-quick-tests">
        <fileset dir="build/testBinDist" includes="build.xml" />
    </subant>
</target>

which is called by the following snippet to produce a nice xml report

                <au:antunit failonerror="@{failonerror}">
                    <propertyset>
                        <propertyref name="config.filename" />
                    </propertyset>
                    <path>
                        <pathelement location="@{antunit}" />
                    </path>
                    <au:plainlistener logLevel="info" />
                    <au:xmllistener todir="build" loglevel="info" />
                </au:antunit>

I understand how to migrate dist-bin to gradle, but I'm not sure what's the right way to migrate test-dist-bin and the au:antunit call.

Answer 1

I think what tom meant is a way to test his own written gradle tasks, right? If you have written a custom gradle task by extending DefaultTask and you put it in the buildSrc folder of your project, you can add a junit/spock/whatever based test class to test your task implementation. Gradles own build provides a good example for that. have a look at

https://github.com/gradle/gradle/blob/master/buildSrc/src/test/groovy/org/gradle/build/docs/dsl/source/ExtractDslMetaDataTaskTest.groovy

This is a spock specification, that tests the ExtractDslMetaDataTask which was specifically written for griddles own build. The ExtractDslMetaDataTask is located at:

https://github.com/gradle/gradle/blob/master/buildSrc/src/main/groovy/org/gradle/build/docs/dsl/source/ExtractDslMetaDataTask.groovy

To add assertions to your build script "adhoc tasks" like your example above you can use the groovy power assertion.

an example: if you have a a very simple task like this in your script:

task writeFoo << {
    file("$buildDir/foo.txt").text =  "bar"
}

you can either modify the task itself to add an assertion:

task writeFoo << {
    file("$buildDir/foo.txt").text =  "bar"
    assert file("$buildDir/foo.txt).isFile()
}

or you add a dedicated test task to your script

task testWriteFoo(dependsOn: writeFoo) << {
    assert file("$buildDir/foo.txt).isFile()
    assert file("$buildDir/foo.txt).text == "bar"
}

remember that you can use the full power of the groovy language in your build scripts.

There are plans to have an integrated testing toolkit in gradle to support build script authors on testing their custom build logic. have a look at:

http://forums.gradle.org/gradle/topics/testing_toolkit_for_custom_build_logic