text: let assert = require('assert');
  const Distances = require('../src/core/distances');
  const Cell = require('../src/core/cell');
  
  let cell1, cell2, distances;
  
  describe('Distances', function() {
      beforeEach(function() {
          cell1 = new Cell(0, 0);
          cell2 = new Cell(2, 5);
          distances = new Distances(cell1);
      });
  
      it('#constructor should initialize member variables', function() {
          assert.equal(distances.distance_of(cell1), 0);
          assert.equal(distances.cells[cell1._hash()], distances.root);
      });
  
      it('#exists should check if distance for cell is defined', function() {
          assert.equal(distances.exists(cell1), true);
          assert.equal(distances.exists(cell2), false);
          distances.store(cell2, 10);
          assert.equal(distances.exists(cell2), true);
      });
  
      it('#store should save distance of cell', function() {
          distances.store(cell2, 11);
          assert.equal(distances.distance_of(cell2), 11);
          assert.equal(distances.cells[cell2._hash()], cell2);
      });
  
  });
  