import info.magnolia.context.MgnlContext;
import info.magnolia.link.LinkTransformerManager;
import info.magnolia.test.junit5.MagnoliaTest;
import info.magnolia.test.mock.MockContext;
import info.magnolia.test.mock.MockRepositoryAcquiringStrategy;
import info.magnolia.test.mock.jcr.MockSession;
import lombok.val;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;

import static info.magnolia.test.mock.MockUtil.getMockContext;
import static info.magnolia.test.mock.MockUtil.initMockContext;
import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;

// If you remove this annotation, the tests succeed
@MagnoliaTest
class LinkTransformerManagerTest {
    @BeforeEach
    void setup() {
        // This is redundant if @MagnoliaTest annotation is used, but needed when removed (ignore if former is the case)
        initMockContext();
    }

    @Test
    void tryCreatingInstance__withoutSpecialSetup() {
        assertDoesNotThrow(LinkTransformerManager::getInstance);
    }

    @Test
    void tryCreatingInstance__withSession() {
        // fyi: same result if ContextSupport.getContext is used
        val context = getMockContext();
        context.addSession("config", new MockSession("config"));

        assertDoesNotThrow(LinkTransformerManager::getInstance);
    }

    @Test
    void tryCreatingInstance__withRepositoryStrategySession() {
        val context = getMockContext();
        val strategy = (MockRepositoryAcquiringStrategy) context.getRepositoryStrategy();
        strategy.addSession("config", new MockSession("config"));

        assertDoesNotThrow(LinkTransformerManager::getInstance);
    }

    @Test
    void tryCreatingInstance__withNewRepositoryStrategySession() {
        val context = getMockContext();
        val strategy = new MockRepositoryAcquiringStrategy();
        strategy.addSession("config", new MockSession("config"));
        context.setRepositoryStrategy(strategy);

        assertDoesNotThrow(LinkTransformerManager::getInstance);
    }

    @Test
    void tryCreatingInstance__withSystemRepositoryStrategySession() {
        val context = (MockContext) MgnlContext.getSystemContext();
        val strategy = (MockRepositoryAcquiringStrategy) context.getRepositoryStrategy();
        strategy.addSession("config", new MockSession("config"));

        assertDoesNotThrow(LinkTransformerManager::getInstance);
    }

    @Test
    void tryCreatingInstance__withNewSystemRepositoryStrategySession() {
        val context = (MockContext) MgnlContext.getSystemContext();
        val strategy = new MockRepositoryAcquiringStrategy();
        strategy.addSession("config", new MockSession("config"));
        context.setRepositoryStrategy(strategy);

        assertDoesNotThrow(LinkTransformerManager::getInstance);
    }
}
 

org.opentest4j.AssertionFailedError: Unexpected exception thrown: info.magnolia.objectfactory.MgnlInstantiationException: Can't instantiate an implementation of this class [info.magnolia.link.LinkTransformerManager]: IllegalArgumentException: session [config] not initialized