grafana/public/app/plugins/panel/graph/specs/histogram.test.ts

import { convertValuesToHistogram, getSeriesValues } from '../histogram';

describe('Graph Histogam Converter', () => {
  describe('Values to histogram converter', () => {
    let values: any;
    let bucketSize = 10;

    beforeEach(() => {
      values = [29, 1, 2, 10, 11, 17, 20];
    });

    it('Should convert to series-like array', () => {
      bucketSize = 10;
      const expected = [
        [0, 2],
        [10, 3],
        [20, 2],
      ];

      const histogram = convertValuesToHistogram(values, bucketSize, 1, 30);
      expect(histogram).toMatchObject(expected);
    });

    it('Should not add empty buckets', () => {
      bucketSize = 5;
      const expected = [
        [0, 2],
        [5, 0],
        [10, 2],
        [15, 1],
        [20, 1],
        [25, 1],
      ];

      const histogram = convertValuesToHistogram(values, bucketSize, 1, 30);
      expect(histogram).toMatchObject(expected);
    });
  });

  describe('Buckets to have correct decimals', () => {
    it('Should convert to series-like array', () => {
      const expected = [[1.7000000000000002, 1]];

      const histogram = convertValuesToHistogram([1.715000033378601], 0.05, 1.7, 1.8);
      expect(histogram).toMatchObject(expected);
    });
  });

  describe('Series to values converter', () => {
    let data: any;

    beforeEach(() => {
      data = [
        {
          datapoints: [
            [1, 0],
            [2, 0],
            [10, 0],
            [11, 0],
            [17, 0],
            [20, 0],
            [29, 0],
          ],
        },
      ];
    });

    it('Should convert to values array', () => {
      const expected = [1, 2, 10, 11, 17, 20, 29];

      const values = getSeriesValues(data);
      expect(values).toMatchObject(expected);
    });

    it('Should skip null values', () => {
      data[0].datapoints.push([null, 0]);

      const expected = [1, 2, 10, 11, 17, 20, 29];

      const values = getSeriesValues(data);
      expect(values).toMatchObject(expected);
    });
  });
});