GraphEdge.test.js

import GraphEdge from '../GraphEdge';
import GraphVertex from '../GraphVertex';

describe('GraphEdge', () => {
  it('should create graph edge with default weight', () => {
    const startVertex = new GraphVertex('A');
    const endVertex = new GraphVertex('B');
    const edge = new GraphEdge(startVertex, endVertex);

    expect(edge.startVertex).toEqual(startVertex);
    expect(edge.endVertex).toEqual(endVertex);
    expect(edge.weight).toEqual(0);
  });

  it('should create graph edge with predefined weight', () => {
    const startVertex = new GraphVertex('A');
    const endVertex = new GraphVertex('B');
    const edge = new GraphEdge(startVertex, endVertex, 10);

    expect(edge.startVertex).toEqual(startVertex);
    expect(edge.endVertex).toEqual(endVertex);
    expect(edge.weight).toEqual(10);
  });

  it('should be possible to do edge reverse', () => {
    const vertexA = new GraphVertex('A');
    const vertexB = new GraphVertex('B');
    const edge = new GraphEdge(vertexA, vertexB, 10);

    expect(edge.startVertex).toEqual(vertexA);
    expect(edge.endVertex).toEqual(vertexB);
    expect(edge.weight).toEqual(10);

    edge.reverse();

    expect(edge.startVertex).toEqual(vertexB);
    expect(edge.endVertex).toEqual(vertexA);
    expect(edge.weight).toEqual(10);
  });

  it('should return edges names as key', () => {
    const edge = new GraphEdge(new GraphVertex('A'), new GraphVertex('B'), 0);

    expect(edge.getKey()).toBe('A_B');
    expect(edge.toString()).toBe('A_B');
  });

  it('should return custom key if defined', () => {
    const edge = new GraphEdge(new GraphVertex('A'), new GraphVertex('B'), 0, 'custom_key');

    expect(edge.getKey()).toEqual('custom_key');
    expect(edge.toString()).toEqual('custom_key');
  });

  it('should execute toString on key  when calling toString on edge', () => {
    const customKey = {
      toString() { return 'custom_key'; },
    };

    const edge = new GraphEdge(new GraphVertex('A'), new GraphVertex('B'), 0, customKey);

    expect(edge.getKey()).toEqual(customKey);
    expect(edge.toString()).toEqual('custom_key');
  });
});