The stubs define three top-level targets that are defined in  LifecycleTaskSegmentCalculatorStub;
clean, aggr and install. "aggr" is an aggregating task while clean and install are lifecyclephases.
There will be three items in the task list for this dataset.

The stubs also exist at different "levels", where one test might wire stubs into a specific live implementation.

import org.apache.maven.execution.MavenSession;
import org.apache.maven.execution.ProjectDependencyGraph;
import org.apache.maven.project.MavenProject;

/**
 * A build context that matches a Maven project to a given task segment, and the session to be used.
 * <p>
 * A note to the reader;
 * </p>
 * <p>
 * There are several issues/discussions regarding how "aggregator" plugins should be handled.

                            pool.shutdown();
                        }
                        return true;
                    }
                };
                pool.submit(task);
                return task;
            });
            result = future.get();
        } catch (Exception e) {
            throw new UnresolvableModelException(e, parent.getGroupId(), parent.getArtifactId(), parent.getVersion());

            // We can't use work stealing, as we are building a graph
            // and this could lead to cycles where a thread waits for
            // a task to finish, then execute another one which waits
            // for the initial task...
            // In order to work around that problem, we override the
            // invokeAll method, so that whenever the method is called,

        return ArtifactUtils.versionlessKey(project.getGroupId(), project.getArtifactId());
    }

    public void registerBuildFailure(MavenProject project, Exception error, String task, long time) {
        buildFailuresByProject.put(getProjectKey(project), new BuildFailure(project, time, error));
    }

    public boolean hasBuildFailures() {
        return !buildFailuresByProject.isEmpty();
    }

    private final List<Task> tasks;

    private final boolean aggregating;

    public TaskSegment(boolean aggregating) {
        this.aggregating = aggregating;
        tasks = new ArrayList<>();
    }

    public TaskSegment(boolean aggregating, Task... tasks) {
        this.aggregating = aggregating;

        final List<MojoExecution> mojoExecutions = new ArrayList<>();

        for (Task task : tasks) {
            if (task instanceof GoalTask) {
                String pluginGoal = task.getValue();

                String executionId = "default-cli";
                int executionIdx = pluginGoal.indexOf('@');
                if (executionIdx > 0) {

                    PluginVersionResolutionException {
        List<TaskSegment> taskSegments = new ArrayList<>(tasks.size());

        TaskSegment currentSegment = null;

        for (String task : tasks) {
            if (aggr.equals(task)) {
                boolean aggregating = true;

                if (currentSegment == null || currentSegment.isAggregating() != aggregating) {

 * </p>
 * <strong>Note:</strong> This interface is part of work in progress and can be changed or removed without notice.
 */
public interface Builder {
    //
    // Be nice to whittle this down to Session, maybe add task segments to the session. The session really is
    // the place to store reactor related information.
    //
    void build(
            MavenSession session,
            ReactorContext reactorContext,

 * under the License.
 */
package org.apache.maven.lifecycle.internal;

/**
 * A task that is a lifecycle.
 * <p>
 * <strong>NOTE:</strong> This class is not part of any public api and can be changed or deleted without prior notice.
 *
 * @since 3.0
 */
public final class LifecycleTask extends Task {
    public LifecycleTask(String lifecyclePhase) {
        super(lifecyclePhase);
    }