SectionManager.jest.js

import SectionManager from './SectionManager';
import {CELLS, SECTION_SIZE} from './TestData';

function initSectionManager() {
  const sectionManager = new SectionManager(SECTION_SIZE);
  CELLS.forEach((cellMetadatum, index) => {
    sectionManager.registerCell({
      cellMetadatum,
      index,
    });
  });
  return sectionManager;
}

function verifySections(
  sectionManager,
  sizeAndPosition,
  expectedSizeAndPositionInfos,
) {
  const sections = sectionManager.getSections(sizeAndPosition);
  expect(sections.length).toEqual(expectedSizeAndPositionInfos.length);
  expectedSizeAndPositionInfos.forEach(sizeAndPosition => {
    const match = sections.find(
      section =>
        section.x === sizeAndPosition.x && section.y === sizeAndPosition.y,
    );
    expect(!!match).toEqual(true);
  });
}

describe('SectionManager', () => {
  it('creates the appropriate number of Sections', () => {
    const sectionManager = initSectionManager();
    expect(sectionManager.getTotalSectionCount()).toEqual(6);
  });

  it('returns the proper Sections based on the specified area', () => {
    const sectionManager = initSectionManager();
    verifySections(sectionManager, {x: 0, y: 0, width: 1, height: 1}, [
      {x: 0, y: 0},
    ]);
    verifySections(sectionManager, {x: 1, y: 1, width: 1, height: 1}, [
      {x: 0, y: 0},
    ]);
    verifySections(sectionManager, {x: 0, y: 0, width: 4, height: 4}, [
      {x: 0, y: 0},
      {x: 2, y: 0},
      {x: 0, y: 2},
      {x: 2, y: 2},
    ]);
    verifySections(sectionManager, {x: 4, y: 0, width: 2, height: 3}, [
      {x: 4, y: 0},
      {x: 4, y: 2},
    ]);
  });

  it('assigns cells to the appropriate sections', () => {
    const sectionManager = initSectionManager();
    expect(
      sectionManager.getCellIndices({x: 0, y: 0, width: 2, height: 2}),
    ).toEqual([0]);
    expect(
      sectionManager.getCellIndices({x: 2, y: 0, width: 2, height: 2}),
    ).toEqual([1, 2, 3]);
    expect(
      sectionManager.getCellIndices({x: 4, y: 0, width: 2, height: 2}),
    ).toEqual([6]);
    expect(
      sectionManager.getCellIndices({x: 0, y: 2, width: 2, height: 2}),
    ).toEqual([4]);
    expect(
      sectionManager.getCellIndices({x: 2, y: 2, width: 2, height: 2}),
    ).toEqual([3, 4, 5]);
    expect(
      sectionManager.getCellIndices({x: 4, y: 2, width: 2, height: 2}),
    ).toEqual([7, 8, 9]);
  });
});