/**
 * @license
 * Copyright Google LLC All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */

import {Statistic} from '../src/statistic';

describe('statistic', () => {
  it('should calculate the mean', () => {
    expect(Statistic.calculateMean([])).toBeNaN();
    expect(Statistic.calculateMean([1, 2, 3])).toBe(2.0);
  });

  it('should calculate the standard deviation', () => {
    expect(Statistic.calculateStandardDeviation([], NaN)).toBeNaN();
    expect(Statistic.calculateStandardDeviation([1], 1)).toBe(0.0);
    expect(Statistic.calculateStandardDeviation([2, 4, 4, 4, 5, 5, 7, 9], 5)).toBe(2.0);
  });

  it('should calculate the coefficient of variation', () => {
    expect(Statistic.calculateCoefficientOfVariation([], NaN)).toBeNaN();
    expect(Statistic.calculateCoefficientOfVariation([1], 1)).toBe(0.0);
    expect(Statistic.calculateCoefficientOfVariation([2, 4, 4, 4, 5, 5, 7, 9], 5)).toBe(40.0);
  });

  it('should calculate the regression slope', () => {
    expect(Statistic.calculateRegressionSlope([], NaN, [], NaN)).toBeNaN();
    expect(Statistic.calculateRegressionSlope([1], 1, [2], 2)).toBeNaN();
    expect(Statistic.calculateRegressionSlope([1, 2], 1.5, [2, 4], 3)).toBe(2.0);
  });
});
