GroupedTaskOutputFixture task = tasks.get(taskName);
        if (task == null) {
            task = new GroupedTaskOutputFixture(taskName);
            tasks.put(taskName, task);
        }

        task.addOutput(taskOutput);
        task.setOutcome(taskOutcome);
    }

    private void consumeTransformOutput(Matcher matcher) {
        String initialSubjectType = matcher.group(1);
        String subject = matcher.group(2);

import static org.gradle.util.internal.CollectionUtils.join;

public abstract class GroupedNodeFixture {

    private final List<String> outputs = new ArrayList<>(1);

    public void addOutput(String transformOutput) {
        outputs.add(transformOutput);
    }

    public String getOutput() {
        List<String> nonEmptyOutputs = filter(outputs, string -> !string.equals(""));

 */
public abstract class GroupedWorkOutputFixture {

    private final List<String> outputs = new ArrayList<>(1);

    /**
     * Adds an output entry to the group.
     */
    public void addOutput(String output) {
        outputs.add(output);
    }

    /**
     * Returns concatenated non-empty output entries.
     */
    public String getOutput() {