Graph2.js : Convert live test into Jest test.

Data-Structures/Graph/Graph2.js

@@ -36,7 +36,7 @@ class Graph {
   }
 
   // Prints the vertex and adjacency list
-  printGraph () {
+  printGraph (output = value => console.log(value)) {
     // get all the vertices
     const getKeys = this.AdjList.keys()
 
@@ -54,35 +54,9 @@ class Graph {
       }
 
       // print the vertex and its adjacency list
-      console.log(i + ' -> ' + conc)
+      output(i + ' -> ' + conc)
     }
   }
 }
-// Example
-const graph = new Graph(6)
-const vertices = ['A', 'B', 'C', 'D', 'E', 'F']
 
-// adding vertices
-for (let i = 0; i < vertices.length; i++) {
-  graph.addVertex(vertices[i])
-}
-
-// adding edges
-graph.addEdge('A', 'B')
-graph.addEdge('A', 'D')
-graph.addEdge('A', 'E')
-graph.addEdge('B', 'C')
-graph.addEdge('D', 'E')
-graph.addEdge('E', 'F')
-graph.addEdge('E', 'C')
-graph.addEdge('C', 'F')
-
-// prints all vertex and
-// its adjacency list
-// A -> B D E
-// B -> A C
-// C -> B E F
-// D -> A E
-// E -> A D F C
-// F -> E C
-graph.printGraph()
+export { Graph }

Data-Structures/Graph/test/Graph2.test.js

@@ -0,0 +1,41 @@
+import { Graph } from '../Graph2'
+
+describe('Test Graph2', () => {
+  const vertices = ['A', 'B', 'C', 'D', 'E', 'F']
+  const graph = new Graph(vertices.length)
+
+  // adding vertices
+  for (let i = 0; i < vertices.length; i++) {
+    graph.addVertex(vertices[i])
+  }
+
+  // adding edges
+  graph.addEdge('A', 'B')
+  graph.addEdge('A', 'D')
+  graph.addEdge('A', 'E')
+  graph.addEdge('B', 'C')
+  graph.addEdge('D', 'E')
+  graph.addEdge('E', 'F')
+  graph.addEdge('E', 'C')
+  graph.addEdge('C', 'F')
+
+  it('Check adjacency lists', () => {
+    const mockFn = jest.fn()
+    graph.printGraph(mockFn)
+
+    // Expect one call per vertex
+    expect(mockFn.mock.calls.length).toBe(vertices.length)
+
+    // Collect adjacency lists from output (call args)
+    const adjListArr = mockFn.mock.calls.map(v => v[0])
+
+    expect(adjListArr).toEqual([
+      'A -> B D E ',
+      'B -> A C ',
+      'C -> B E F ',
+      'D -> A E ',
+      'E -> A D F C ',
+      'F -> E C '
+    ])
+  })
+})