🔗Testing Plugins

🔗Test Framework for Plugins

The Test Framework provides methods to create and deploy JAR files as artifacts. This lets you test the creation of multiple applications from the same artifact, as well as the use of plugin artifacts.

To add an artifact containing an application class:

// Add the artifact for a Data Pipeline app
addAppArtifact(new ArtifactId(NamespaceId.DEFAULT.getNamespace(), "data-pipeline", "3.5.0"),
  DataPipelineApp.class,
  BatchSource.class.getPackage().getName(),
  Action.class.getPackage().getName(),
  PipelineConfigurable.class.getPackage().getName(),
  "org.apache.avro.mapred", "org.apache.avro", "org.apache.avro.generic");

The first argument is the id of the artifact; the second is the application class; and the remainder of the arguments are packages that should be included in the Export-Packages manifest attribute bundled in the JAR. The framework will trace the dependencies of the specified application class to create a JAR with those dependencies. This will mimic what happens when you actually build your application JAR using maven.

An application can then be deployed using that artifact:

// Create application create request
ETLBatchConfig etlConfig = new ETLBatchConfig("* * * * *", source, sink, transformList);
AppRequest<ETLBatchConfig> appRequest = new AppRequest<>(new ArtifactSummary("etlbatch", "3.5.0"), etlConfig);
ApplicationId appId = NamespaceId.DEFAULT.app("KVToKV");

// Deploy the application
ApplicationManager appManager = deployApplication(appId, appRequest);

Plugins extending the artifact can also be added:

// Add some test plugins
addPluginArtifact(new ArtifactId(NamespaceId.DEFAULT.getNamespace(), "spark-plugins", "1.0.0"),
                  APP_ARTIFACT_ID,
                  NaiveBayesTrainer.class, NaiveBayesClassifier.class);

The first argument is the id of the plugin artifact; the second is the parent artifact it is extending; and the remainder of the arguments are classes that should be bundled in the JAR. The packages of all these classes are included in the Export-Packages manifest attribute bundled in the JAR. When adding a plugin artifact this way, it is important to include all classes in your plugin packages, even if they are not used in your test case. This is to ensure that the JAR can trace all required dependencies to correctly build the JAR.

The examples are taken from the DataPipelineTest and HydratorTestBase classes of CDAP pipelines.

🔗CDAP Pipelines Test Module

Additional information on unit testing with CDAP is in the Developers’ Manual section on Testing a CDAP Application.

In addition, CDAP provides a hydrator-test module that contains several mock plugins for you to use in tests with your custom plugins. To use the module, add a dependency to your pom.xml:

<dependency>
  <groupId>co.cask.cdap</groupId>
  <artifactId>hydrator-test</artifactId>
  <version>${cdap.version}</version>
  <scope>test</scope>
</dependency>

Then extend the HydratorTestBase class, and create a method that will setup up the application artifact and mock plugins, as well as the artifact containing your custom plugins:

/**
 * Unit tests for our plugins.
 */
public class PipelineTest extends HydratorTestBase {
  private static final ArtifactSummary APP_ARTIFACT = new ArtifactSummary("cdap-data-pipeline", "1.0.0");
  @ClassRule
  public static final TestConfiguration CONFIG = new TestConfiguration("explore.enabled", false);

  @BeforeClass
  public static void setupTestClass() throws Exception {
    ArtifactId parentArtifact = NamespaceId.DEFAULT.artifact(APP_ARTIFACT.getName(), APP_ARTIFACT.getVersion());

    // Add the data pipeline artifact and mock plugins.
    setupBatchArtifacts(parentArtifact, DataPipelineApp.class);

    // Add our plugins artifact with the data pipeline artifact as its parent.
    // This will make our plugins available to the data pipeline.
    addPluginArtifact(NamespaceId.DEFAULT.artifact("example-plugins", "1.0.0"),
                      parentArtifact,
                      TextFileSetSource.class,
                      TextFileSetSink.class,
                      WordCountAggregator.class,
                      WordCountCompute.class,
                      WordCountSink.class);
  }

You can then add test cases as you see fit. The cdap-data-pipeline-plugins-archetype includes an example of this unit test.