package org.apache.maven.repository.internal;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

import org.eclipse.aether.RepositorySystem;
import org.eclipse.aether.impl.MetadataGeneratorFactory;
import org.eclipse.aether.spi.locator.ServiceLocator;
import org.junit.jupiter.api.Test;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotNull;

public class MavenRepositorySystemUtilsTest
{

    @Test
    public void testGetRepositorySystem()
    {
        ServiceLocator locator = MavenRepositorySystemUtils.newServiceLocator();
        RepositorySystem repoSys = locator.getService( RepositorySystem.class );
        assertNotNull( repoSys );
    }

    @Test
    public void testGetMetadataGeneratorFactories()
    {
        ServiceLocator locator = MavenRepositorySystemUtils.newServiceLocator();
        assertEquals( 2, locator.getServices( MetadataGeneratorFactory.class ).size() );
    }

}

package org.apache.maven.repository.internal;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

import org.eclipse.aether.RepositorySystem;
import org.eclipse.aether.RepositorySystemSession;
import org.eclipse.aether.impl.MetadataGeneratorFactory;
import org.eclipse.aether.spi.locator.ServiceLocator;
import org.junit.jupiter.api.Test;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotNull;

public class MavenRepositorySystemUtilsTest
{

    @Test
    public void testNewSession()
    {
        RepositorySystemSession session = MavenRepositorySystemUtils.newSession();
        assertNotNull( session );
    }

    @Test
    public void testGetRepositorySystem()
    {
        ServiceLocator locator = MavenRepositorySystemUtils.newServiceLocator();
        RepositorySystem repoSys = locator.getService( RepositorySystem.class );
        assertNotNull( repoSys );
    }

    @Test
    public void testGetMetadataGeneratorFactories()
    {
        ServiceLocator locator = MavenRepositorySystemUtils.newServiceLocator();
        assertEquals( 2, locator.getServices( MetadataGeneratorFactory.class ).size() );
    }

}

Add a unit test for MavenRepositorySystemUtils#newSession