@Nonnull
    Map<String, String> getUserProperties();

    /**
     * Returns immutable system properties to use for interpolation. The system properties are collected from the
     * runtime environment such as {@link System#getProperties()} and environment variables
     * (prefixed with {@code env.}).
     *
     * @return the system properties, never {@code null}
     */
    @Nonnull
    Map<String, String> getSystemProperties();

/**
 * Test cases for the project {@code ModelResolver} implementation.
 */
class DefaultModelResolverTest {

    Session session;

    @BeforeEach
    void setup() {
        Path basedir = Paths.get(System.getProperty("basedir", ""));
        Path localRepoPath = basedir.resolve("target/local-repo");
        Path remoteRepoPath = basedir.resolve("src/test/remote-repo");
        Session s = ApiRunner.createSession();

    }

    //
    // Implementation
    //

    private File findArtifact(MavenProject project, Artifact artifact) {
        // POMs are always returned from the file system
        if ("pom".equals(artifact.getExtension())) {
            return project.getFile();
        }

        // First check in the project local repository

        resolutionErrorHandler.throwErrors(request, result);
        assertEquals(2, result.getArtifacts().size());

        //
        // System scoped version which should
        //
        d.setScope(Artifact.SCOPE_SYSTEM);
        File file = new File(getBasedir(), "src/test/repository-system/maven-core-2.1.0.jar");
        assertTrue(file.exists());
        d.setSystemPath(file.getCanonicalPath());

        session.setArtifactDescriptorPolicy(getArtifactDescriptorPolicy());
        session.setScopeManager(getScopeManager());
    }

    /**
     * Creates a new Maven-like repository system session by initializing the session with values typical for
     * Maven-based resolution. In more detail, this method configures settings relevant for the processing of dependency

import org.eclipse.aether.RepositoryCache;
import org.eclipse.aether.RepositorySystemSession;

import static java.util.Objects.requireNonNull;

/**
 * A model builder cache backed by the repository system cache.
 *
 */
public class DefaultModelCache implements ModelCache {
    private static final String KEY = DefaultModelCache.class.getName();

    @SuppressWarnings("unchecked")

 * thrown away immediately once repository system was created and there is no need for more instances. If new
 * repository system instance needed, new instance of this class must be created. For proper shut down of returned
 * repository system instance(s) use {@link RepositorySystem#shutdown()} method on supplied instance(s).
 * <p>

    /**
     * List of profile ids that have been explicitly deactivated by the user.
     */
    @Nonnull
    List<String> getInactiveProfileIds();

    /**
     * Provides a map of system properties.
     */
    @Nonnull
    Map<String, String> getSystemProperties();

    /**
     * Provides a map of user properties.
     * User properties
     */
    @Nonnull

                            key,
                            "must be empty, imported POM cannot have a classifier.",
                            dependency);
                }
            } else if ("system".equals(dependency.getScope())) {

                if (request.getValidationLevel() >= ModelBuilderRequest.VALIDATION_LEVEL_MAVEN_3_1) {
                    addViolation(
                            problems,

    }

    @CanIgnoreReturnValue
    Builder<K, V> combine(ImmutableSortedMap.Builder<K, V> other) {
      ensureCapacity(size + other.size);
      System.arraycopy(other.keys, 0, this.keys, this.size, other.size);
      System.arraycopy(other.values, 0, this.values, this.size, other.size);
      size += other.size;
      return this;
    }

    /**
     * Returns a newly-created immutable sorted map.