OSGi Mocks

Mock implementation of selected OSGi APIs for easier testing.

Maven Dependency

For JUnit 5:

<dependency>
  <groupId>org.apache.sling</groupId>
  <artifactId>org.apache.sling.testing.osgi-mock.junit5</artifactId>
</dependency>

For JUnit 4:

<dependency>
  <groupId>org.apache.sling</groupId>
  <artifactId>org.apache.sling.testing.osgi-mock.junit4</artifactId>
</dependency>

See latest version on the downloads page.

There are two major version ranges available:

• osgi-mock 1.x: compatible with OSGi R4 and above, JUnit 4
• osgi-mock 2.x: compatible with OSGi R6 and above, JUnit 4 and JUnit 5

Implemented mock features

The mock implementation supports:

• Instantiating OSGi Bundle, BundleContext and ComponentContext objects and navigate between them.
• Register OSGi SCR services and get references to service instances
• Supports reading OSGi SCR metadata from /OSGI-INF/<pid>.xml and from /OSGI-INF/serviceComponents.xml
• Apply service properties/component configuration provided in unit test and from SCR metadata
• Inject SCR dependencies - static and dynamic
• Call lifecycle methods for activating, deactivating or modifying SCR components
• Service and bundle listener implementation
• Mock implementation of LogService which logs to SLF4J in JUnit context
• Mock implementation of EventAdmin which supports EventHandler services
• Mock implementation of ConfigAdmin
• Context Plugins

Since osgi-mock 2.0.0:

• Support OSGi R6 and Declarative Services 1.3: Field-based reference bindings and component property types

Usage

The OsgiContext object provides access to mock implementations of:

• OSGi Component Context
• OSGi Bundle Context

Additionally it supports:

• Registering and activating OSGi services and inject dependencies

JUnit 5: OSGi Context JUnit Extension

The OSGi mock context can be injected into a JUnit test using a custom JUnit extension named OsgiContextExtension. This extension takes care of all initialization and cleanup tasks required to make sure all unit tests can run independently (and in parallel, if required).

Example:

@ExtendWith(OsgiContextExtension.class)
public class ExampleTest {

  private final OsgiContext context = new OsgiContext();

  @Test
  public void testSomething() {

    // register and activate service with configuration
    MyService service1 = context.registerInjectActivateService(new MyService(),
        "prop1", "value1");

    // get service instance
    OtherService service2 = context.getService(OtherService.class);

  }

}

It is possible to combine such a unit test with a @ExtendWith annotation e.g. for Mockito JUnit Jupiter Extension.

JUnit 4: OSGi Context JUnit Rule

The OSGi mock context can be injected into a JUnit test using a custom JUnit rule named OsgiContext. This rule takes care of all initialization and cleanup tasks required to make sure all unit tests can run independently (and in parallel, if required).

Example:

public class ExampleTest {

  @Rule
  public final OsgiContext context = new OsgiContext();

  @Test
  public void testSomething() {

    // register and activate service with configuration
    MyService service1 = context.registerInjectActivateService(new MyService(),
        "prop1", "value1");

    // get service instance
    OtherService service2 = context.getService(OtherService.class);

  }

}

It is possible to combine such a unit test with a @RunWith annotation e.g. for Mockito JUnit Runner.

Getting OSGi mock objects

The factory class MockOsgi allows to instantiate the different mock implementations.

Example:

// get bundle context
BundleContext bundleContext = MockOsgi.newBundleContext();

// get component context with configuration
BundleContext bundleContext = MockOsgi.newComponentContext(properties,
    "prop1", "value1");

It is possible to simulate registering of OSGi services (backed by a simple hash map internally):

// register service
bundleContext.registerService(MyClass.class, myService, properties);

// get service instance
ServiceReference ref = bundleContext.getServiceReference(MyClass.class.getName());
MyClass service = bundleContext.getService(ref);

Activation and Dependency Injection

It is possible to simulate OSGi service activation, deactivation and dependency injection and the mock implementation tries to to its best to execute all as expected for an OSGi environment.

Example:

// get bundle context
BundleContext bundleContext = MockOsgi.newBundleContext();

// create service instance manually
MyService service = new MyService();

// inject dependencies
MockOsgi.injectServices(service, bundleContext);

// activate service
MockOsgi.activate(service, props);

// operate with service...

// deactivate service
MockOsgi.deactivate(service);

Please note:

• You should ensure that you register you services in the correct order of their dependency chain. Only dynamic references will be handled automatically independent of registration order.
• The injectServices, activate and deactivate Methods can only work properly when the SCR XML metadata files are preset in the classpath at /OSGI-INF. They are generated automatically by the Maven SCR plugin, but might be missing if your clean and build the project within your IDE (e.g. Eclipse). In this case you have to compile the project again with maven and can run the tests - or use a Maven IDE Integration like m2eclipse.

Provide your own configuration via ConfigAdmin

If you want to provide your own configuration to an OSGi service that you do not register and activate itself in the mock context you can provide your own custom OSGi configuration via the mock implementation of the ConfigAdmin service.

Example:

ConfigurationAdmin configAdmin = context.getService(ConfigurationAdmin.class);
Configuration myServiceConfig = configAdmin.getConfiguration(MY_SERVICE_PID);
Dictionary<String, Object> props = new Hashtable<String, Object>();
props.put("prop1", "value1");
myServiceConfig.update(props);

Context Plugins

OSGi Mocks supports "Context Plugins" that hook into the lifecycle of each test run and can prepare test setup before or after the other setUp actions, and execute test tear down code before or after the other tearDown action.

To define a plugin implement the org.apache.sling.testing.mock.osgi.context.ContextPlugin<OsgiContextImpl> interface. For convenience it is recommended to extend the abstract class org.apache.sling.testing.mock.osgi.context.AbstractContextPlugin<OsgiContextImpl>. These plugins can be used with OSGi Mock context, but also with context instances deriving from it like Sling Mocks and AEM Mocks. In most cases you would just override the afterSetUp method. In this method you can register additional OSGi services or do other preparation work. It is recommended to define a constant pointing to a singleton of a plugin instance for using it.

To use a plugin in your unit test class, use the OsgiContextBuilder class instead of directly instantiating the OsgiContextclass. This allows you in a fluent style to configure more options, with the plugin(...) method you can add one or more plugins.

Example:

OsgiContext context = new OsgiContextBuilder().plugin(MY_PLUGIN).build();

More examples:

• Apache Sling Context-Aware Configuration Mock Plugin
• Apache Sling Context-Aware Configuration Mock Plugin Test