public void testSingleQuantile_median() {
    double referenceValue = REFERENCE_ALGORITHM.singleQuantile(1, 2, dataset.clone());
    for (QuantilesAlgorithm algorithm : NON_REFERENCE_ALGORITHMS) {
      assertWithMessage("Mismatch between %s and %s", algorithm, REFERENCE_ALGORITHM)
          .that(algorithm.singleQuantile(1, 2, dataset.clone()))
          .isWithin(ALLOWED_ERROR)
          .of(referenceValue);
    }
  }

    if (getList().size() != expectedList.size()) {
      fail("size mismatch: " + reportContext(expectedList));
    }
    for (int i = 0; i < expectedList.size(); i++) {
      E expected = expectedList.get(i);
      E actual = getList().get(i);
      if (expected != actual && (expected == null || !expected.equals(actual))) {
        fail("mismatch at index " + i + ": " + reportContext(expectedList));
      }
    }
  }

    if (getList().size() != expectedList.size()) {
      fail("size mismatch: " + reportContext(expectedList));
    }
    for (int i = 0; i < expectedList.size(); i++) {
      E expected = expectedList.get(i);
      E actual = getList().get(i);
      if (expected != actual && (expected == null || !expected.equals(actual))) {
        fail("mismatch at index " + i + ": " + reportContext(expectedList));
      }
    }
  }

          + "adjacentNode(node) if you already have a node, or nodeU()/nodeV() if you don't.";
  static final String EDGE_ALREADY_EXISTS = "Edge %s already exists in the graph.";
  static final String ENDPOINTS_MISMATCH =
      "Mismatch: endpoints' ordering is not compatible with directionality of the graph";

  /** Singleton edge value for {@link Graph} implementations backed by {@link ValueGraph}s. */
  enum Presence {
    EDGE_EXISTS
  }