/**
     * Gets the severity level of this problem.
     *
     * @return the severity level of this problem, never {@code null}
     */
    @Nonnull
    Severity getSeverity();

    /**
     * The different severity levels for a problem, in decreasing order.
     *
     * @since 4.0.0
     */
    @Experimental
    enum Severity {
        FATAL, //
        ERROR, //
        WARNING //
    }

   * as a {@link LinkedHashSet}. All list tests and sorted-collection tests automatically specify
   * this feature.
   */
  KNOWN_ORDER,

  /**
   * Indicates that a collection has a different {@link Object#toString} representation than most
   * collections. If not specified, the collection tests will examine the value returned by {@link
   * Object#toString}.
   */
  NON_STANDARD_TOSTRING,

  /**

 *
 * <p>To use, create a new {@link EquivalenceTester} and add equivalence groups where each group
 * contains objects that are supposed to be equal to each other. Objects of different groups are
 * expected to be unequal. For example:
 *
 * <pre>{@code
 * EquivalenceTester.of(someStringEquivalence)
 *     .addEquivalenceGroup("hello", "h" + "ello")
 *     .addEquivalenceGroup("world", "wor" + "ld")

 *
 * <p>To use, create a new {@link EquivalenceTester} and add equivalence groups where each group
 * contains objects that are supposed to be equal to each other. Objects of different groups are
 * expected to be unequal. For example:
 *
 * <pre>{@code
 * EquivalenceTester.of(someStringEquivalence)
 *     .addEquivalenceGroup("hello", "h" + "ello")
 *     .addEquivalenceGroup("world", "wor" + "ld")

  // When Kubernetes does topology aware provisioning, it can use this list to
  // determine which labels it should retrieve from the node object and pass
  // back to the driver.
  // It is possible for different nodes to use different topology keys.
  // This can be empty if driver does not support topology.
  // +optional
  repeated string topologyKeys = 3;

   *
   * Prior to OkHttp 3.3.1 we accepted either form and consider them equivalent. And since OkHttp
   * 3.7.0 this is also true. But OkHttp 3.3.1 through 3.6.0 treated these as different.
   */
  @Test
  fun forJavaName_fromLegacyEnumName() {
    // These would have been considered equal in OkHttp 3.3.1, but now aren't.
    assertThat(forJavaName("SSL_RSA_EXPORT_WITH_RC4_40_MD5"))

 *   <li>comparing each object against an instance of an incompatible class returns false
 *   <li>comparing each pair of objects within the same equality group returns true
 *   <li>comparing each pair of objects from different equality groups returns false
 *   <li>the hash codes of any two equal objects are equal
 * </ul>
 *
 * <p>When a test fails, the error message labels the objects involved in the failed comparison as
 * follows:
 *

				// baseDir's parent being present, retry it once such
				// that the MkdirAll is retried once for the parent
				// of dirPath.
				// Because it is worth a retry to skip a different
				// baseDir which is slightly higher up the depth.
				nbaseDir := path.Dir(baseDir)
				if baseDir != "" && nbaseDir != "" && nbaseDir != SlashSeparator {
					baseDir = nbaseDir
				}
				continue
			}

   * Ordering.natural())}.
   *
   * @param elements the original iterable whose elements have to be permuted.
   * @return an immutable {@link Collection} containing all the different permutations of the
   *     original iterable.
   * @throws NullPointerException if the specified iterable is null or has any null elements.
   * @since 12.0
   */

  // here to provide error messages.
  // TODO(user): Some Strings used in the subclasses can be added as static Strings
  // here too.
  static final String ERROR_PARALLEL_EDGE = "connected by a different edge";
  static final String ERROR_REUSE_EDGE = "it cannot be reused to connect";
  static final String ERROR_MODIFIABLE_COLLECTION =
      "Collection returned is unexpectedly modifiable";