data-structures-again/src/graph/index.test.js

A Javascript library of simple data structures

const { Graph, DepthFirstPath, BreathFirstSearch } = require('.')

describe('test graph DS', () => {
    it('should construct an empty graph', () => {
        const graph = new Graph()
        expect(graph).toBeDefined()
    })

    it('should construct a directed graph', () => {
        const graph = new Graph()

        /*
            a---> b
            ^    /
            |   /
              c
        */

        graph.addEdge('a', 'b')
        graph.addEdge('c', 'a')
        graph.addEdge('c', 'b')

        expect(graph.adjTo('a')).toEqual(['b'])
        expect(graph.adjTo('c')).toEqual(['a', 'b'])
    })

    it('should do bfs', () => {
        const graph = new Graph()

        /*
            a ------> b
            |         ^
            |        /
            >c ----> d
        */

        graph.addEdge('a', 'c')
        graph.addEdge('c', 'b')
        graph.addEdge('c', 'd')
        graph.addEdge('a', 'b')

        const bfsResult = new BreathFirstSearch(graph, 'a')

        expect(bfsResult.hasPathTo('d')).toBe(true)
        expect(bfsResult.pathTo('b')).toEqual(['a', 'b'])
        expect(bfsResult.pathTo('d')).toEqual(['a', 'c', 'd'])
        expect(bfsResult.distanceTo('d')).toEqual(2)
        expect(bfsResult.distanceTo('b')).toEqual(1)
    })

    it('should do dfs', () => {
        const graph = new Graph()

        /*
            a ------> b
            |         ^
            |        /
            >c ----> d
        */

        graph.addEdge('a', 'c')
        graph.addEdge('c', 'b')
        graph.addEdge('c', 'd')
        graph.addEdge('a', 'b')

        const dfsResult = new DepthFirstPath(graph, 'a')

        expect(dfsResult.hasPathTo('c')).toBe(true)
        expect(dfsResult.pathTo('d')).toEqual(['a', 'c', 'd'])
    })

    it('should remove the given edge', () => {
        const graph = new Graph()

        /*
            a ---> b
            |     ^
            |    /
            >  c
        */

        graph.addEdge('a', 'c')
        graph.addEdge('c', 'b')
        graph.addEdge('a', 'b')

        graph.removeEdge('a', 'b')

        expect(graph.adjTo('a')).toEqual(['c'])
    })

    it('should do non-recursive dfs', () => {
        const graph = new Graph()

        /*
            a ---- b
            |      |
            |      |
            c ---- d
        */

        graph.addEdge('a', 'c')
        graph.addEdge('d', 'b')
        graph.addEdge('c', 'd')
        graph.addEdge('a', 'b')

        const dfsResult = new DepthFirstPath(graph, 'a', false)

        expect(dfsResult.hasPathTo('c')).toBe(true)
        expect(dfsResult.pathTo('c')).toEqual(['a', 'c'])
        expect(dfsResult.pathTo('d')).toEqual(['a', 'c', 'd'])
        expect(dfsResult.pathTo('b')).toEqual(['a', 'c', 'd', 'b'])
    })
})