context.put("project.baseUri", "myBaseUri");
    }

    protected void assertProblemFree(SimpleProblemCollector collector) {
        assertEquals(0, collector.getErrors().size(), "Expected no errors");
        assertEquals(0, collector.getWarnings().size(), "Expected no warnings");
        assertEquals(0, collector.getFatals().size(), "Expected no fatals");
    }

    @SuppressWarnings("SameParameterValue")

  @SuppressWarnings({"rawtypes", "unchecked"})
  static <E> Collector<E, ?, ImmutableList<E>> toImmutableList() {
    return (Collector) TO_IMMUTABLE_LIST;
  }

  // Sets

  @SuppressWarnings({"rawtypes", "unchecked"})
  static <E> Collector<E, ?, ImmutableSet<E>> toImmutableSet() {
    return (Collector) TO_IMMUTABLE_SET;
  }

  static <E> Collector<E, ?, ImmutableSortedSet<E>> toImmutableSortedSet(

  @SuppressWarnings({"rawtypes", "unchecked"})
  static <E> Collector<E, ?, ImmutableList<E>> toImmutableList() {
    return (Collector) TO_IMMUTABLE_LIST;
  }

  // Sets

  @SuppressWarnings({"rawtypes", "unchecked"})
  static <E> Collector<E, ?, ImmutableSet<E>> toImmutableSet() {
    return (Collector) TO_IMMUTABLE_SET;
  }

  static <E> Collector<E, ?, ImmutableSortedSet<E>> toImmutableSortedSet(

		}
	}

	// Prepare to register the collectors. Other than `MetricGroup` collectors,
	// we also have standard collectors like `GoCollector`.

	// Create all Non-`MetricGroup` collectors here.
	collectors := map[collectorPath]prometheus.Collector{
		debugGoCollectorPath: collectors.NewGoCollector(),
	}

	// Add all `MetricGroup` collectors to the map.
	for _, mg := range allMetricGroups {

import com.google.common.base.Equivalence;
import com.google.common.collect.ImmutableSortedMap.Builder;
import com.google.common.collect.testing.ListTestSuiteBuilder;
import com.google.common.collect.testing.MapTestSuiteBuilder;
import com.google.common.collect.testing.NavigableMapTestSuiteBuilder;
import com.google.common.collect.testing.features.CollectionFeature;
import com.google.common.collect.testing.features.CollectionSize;

  public static <T extends @Nullable Object> Collector<T, ?, List<T>> least(
      int k, Comparator<? super T> comparator) {
    checkNonnegative(k, "k");
    checkNotNull(comparator);
    return Collector.of(
        () -> TopKSelector.<T>least(k, comparator),
        TopKSelector::offer,
        TopKSelector::combine,
        TopKSelector::topK,
        Collector.Characteristics.UNORDERED);
  }

  /**

     */
    @Nonnull
    Stream<P> problems(BuilderProblem.Severity severity);

    /**
     * Creates an "empty" problem collector that doesn't store any problems.
     *
     * @param <P> the type of problem
     * @return an empty problem collector
     */
    @Nonnull
    static <P extends BuilderProblem> ProblemCollector<P> empty() {
        return new ProblemCollector<>() {

import com.google.common.base.Equivalence;
import com.google.common.collect.ImmutableSet.Builder;
import com.google.common.collect.testing.ListTestSuiteBuilder;
import com.google.common.collect.testing.SetTestSuiteBuilder;
import com.google.common.collect.testing.TestStringSetGenerator;
import com.google.common.collect.testing.features.CollectionFeature;
import com.google.common.collect.testing.features.CollectionSize;

    checkNonnegative(k, "k");
    checkNotNull(comparator);
    return Collector.of(
        () -> TopKSelector.<T>least(k, comparator),
        TopKSelector::offer,
        TopKSelector::combine,
        TopKSelector::topK,
        Collector.Characteristics.UNORDERED);
  }

  /**
   * Returns a {@code Collector} that returns the {@code k} greatest (relative to the specified

  }

  /**
   * A predicate that is expected to return true subsequent to finalization, that is, one
   * of the following actions taken by the garbage collector when performing a full collection in
   * response to {@link System#gc()}:
   *
   * <ul>
   *   <li>invoking the {@code finalize} methods of unreachable objects
   *   <li>clearing weak references to unreachable referents