OSGi BND test Rule - DRY

import lombok.Builder;
import lombok.Getter;
import lombok.extern.slf4j.Slf4j;
import org.junit.rules.ExternalResource;
import org.osgi.framework.BundleContext;
import org.osgi.util.tracker.ServiceTracker;

import static org.junit.Assert.assertNotNull;

@Slf4j
public class ServiceTrackerRule<T> extends ExternalResource {

    private final BundleContext context ;//= FrameworkUtil.getBundle(ServiceTrackerRule.class).getBundleContext();

    private ServiceTracker<T, T> serviceTracker;

    @Getter
    private T service;

    private final Class<T> type;

    @Builder
    public ServiceTrackerRule(BundleContext context, Class<T> type) {
        this.context = context;
        this.type = type;
    }

    @Override
    protected void before() throws Throwable {
        log.info("BEFORE: {}", context);
        serviceTracker = new ServiceTracker<T,T>(context, type, null);
        serviceTracker.open();
        service = serviceTracker.waitForService(1000);
        assertNotNull(type + " service not found", service);
    }

    @Override
    protected void after() {
        serviceTracker.close();
        log.info("AFTER");
    }

}

@test

...
service.getService()
...