* Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.

#include "unittest.hpp"

static const double epsilon = 1e-6;

// Some basic formula tests with confidence = 0.0

TEST_VM(G1Predictions, basic_predictions) {

  G1Predictions predictor(0.0);

  TruncatedSeq s;

  double p0 = predictor.get_new_prediction(&s);

  ASSERT_LT(p0, epsilon) << "Initial prediction of empty sequence must be 0.0";

  s.add(5.0);

  double p1 = predictor.get_new_prediction(&s);

  ASSERT_NEAR(p1, 5.0, epsilon);

  for (int i = 0; i < 40; i++) {

    s.add(5.0);

  double p2 = predictor.get_new_prediction(&s);

  ASSERT_NEAR(p2, 5.0, epsilon);

// The following tests checks that the initial predictions are based on

// the average of the sequence and not on the stddev (which is 0).

TEST_VM(G1Predictions, average_not_stdev_predictions) {

  G1Predictions predictor(0.5);

  TruncatedSeq s;

  s.add(1.0);

  double p1 = predictor.get_new_prediction(&s);

  ASSERT_GT(p1, s.davg()) << "First prediction must be greater than average";

  s.add(1.0);

  double p2 = predictor.get_new_prediction(&s);

  ASSERT_GT(p1, p2) << "First prediction must be greater than second";

  s.add(1.0);

  double p3 = predictor.get_new_prediction(&s);

  ASSERT_GT(p2, p3) << "Second prediction must be greater than third";

  s.add(1.0);

  s.add(1.0); // Five elements are now in the sequence.

  double p4 = predictor.get_new_prediction(&s);

  ASSERT_LT(p4, p3) << "Fourth prediction must be smaller than third";

  ASSERT_NEAR(p4, 1.0, epsilon);

// The following tests checks that initially prediction based on

// the average is used, that gets overridden by the stddev prediction at

// the end.

TEST_VM(G1Predictions, average_stdev_predictions) {

  G1Predictions predictor(0.5);

  TruncatedSeq s;

  s.add(0.5);

  double p1 = predictor.get_new_prediction(&s);

  ASSERT_GT(p1, s.davg()) << "First prediction must be greater than average";

  s.add(0.2);

  double p2 = predictor.get_new_prediction(&s);

  ASSERT_GT(p1, p2) << "First prediction must be greater than second";

  s.add(0.5);

  double p3 = predictor.get_new_prediction(&s);

  ASSERT_GT(p2, p3) << "Second prediction must be greater than third";

  s.add(0.2);

  s.add(2.0);

  double p4 = predictor.get_new_prediction(&s);

  ASSERT_GT(p4, p3) << "Fourth prediction must be greater than third";

}