ok-testing-reloaded-medium

SparkApplicationTest.java

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.TYPE)
public @interface SparkApplicationTest {

  /** SparkApplication that will be tested */
  Class<? extends SparkApplication> value();

  /** Port number for the embedded web server */
  int port() default spark.Service.SPARK_DEFAULT_PORT;
}

SparkRunner.java

import static spark.Spark.awaitInitialization;
import static spark.Spark.port;
import static spark.Spark.stop;

public class SparkRunner extends BlockJUnit4ClassRunner {

  private Class<? extends SparkApplication> sparkApplication;
  private int sparkPort;

  public SparkRunner(Class<?> testClass) throws InitializationError {
    super(testClass);
  }

  @Override
  public void run(RunNotifier notifier) {
    scanAnnotation();
    try {
      sparkBootstrap();
    } catch (Exception e) {
      notifier.fireTestFailure(new Failure(getDescription(), e));
    }

    super.run(notifier);

    sparkShutdown();
  }

  private void scanAnnotation() {
    SparkApplicationTest annotation = getTestClass()
      .getAnnotation(SparkApplicationTest.class);

    sparkApplication = annotation.value();
    sparkPort = annotation.port();
  }

  private void sparkBootstrap() throws IllegalAccessException, InstantiationException {
    port(sparkPort);

    sparkApplication.newInstance().init();

    awaitInitialization();
  }

  private void sparkShutdown() {
    stop();
  }
}

TwitterAppTest.java

import static org.assertj.core.api.Assertions.assertThat;

@RunWith(SparkRunner.class)
@SparkApplicationTest(value = TwitterApp.class, port = 4444)
public class TwitterAppTest {

  @Test
  public void test() throws IOException {
    final OkHttpClient okHttpClient = new OkHttpClient.Builder().build();

    final Request request = new Request.Builder()
      .get()
      .url("http://localhost:4444")
      .build();

    final Response response = okHttpClient.newCall(request).execute();

    assertThat(response.body().string()).isEqualTo("Hello again!");
  }
}