The graph.g file consists of a structure of vertex to vertex. In the following graph.g file, if we align 1 to 2, this means that there is an edge between vertex ID 1 and vertex ID 2. The second line means that there's an edge from vertex ID 1 to 3, then from 2 to 3, and finally 3 to 5:

1  2
1  3
2  3
3  5

We will take the graph.g file, load it, and see how it will provide results in Spark. First, we need to get a resource to our graph.g file. We will do this using the getClass.getResource() method to get the path to it, as follows:

package com.tomekl007.chapter_7

import org.apache.spark.SparkContext
import org.apache.spark.sql.SparkSession
import org.scalatest.FunSuite

class CreatingGraph extends FunSuite {
  val spark: SparkContext = SparkSession.builder().master("local[2]").getOrCreate().sparkContext

  test("should load graph from a file") {
    //given
    val path = getClass.getResource("/graph.g").getPath