Playing with scala-graph API / published by https://github.com/dacr/code-examples-manager #41be75cf-c7c1-486c-a9f0-65d1c971d588/bfee2d46b3182d614444fa790e06abb41d2a5691

scala-graph-1.sc

// summary : Playing with scala-graph API
// keywords : scala, scala-graph, @testable
// publish : gist
// authors : David Crosson
// license : Apache NON-AI License Version 2.0 (https://raw.githubusercontent.com/non-ai-licenses/non-ai-licenses/main/NON-AI-APACHE2)
// id : 41be75cf-c7c1-486c-a9f0-65d1c971d588
// created-on : 2021-12-30T09:03:58+01:00
// managed-by : https://github.com/dacr/code-examples-manager
// run-with : scala-cli $file

// ---------------------
//> using scala "2.13.14"
//> using dep "org.scalatest::scalatest:3.2.16"
//> using dep "org.scala-graph::graph-core:1.13.3"
//> using dep "org.scala-graph::graph-dot:1.13.3"
//> using objectWrapper
// ---------------------

// https://www.scala-graph.org/
// https://en.wikipedia.org/wiki/DOT_(graph_description_language)

import org.scalatest._
import org.scalatest.concurrent.Eventually._
import flatspec._, matchers._, OptionValues._

import scalax.collection.Graph // or scalax.collection.mutable.Graph
import scalax.collection.GraphPredef._, scalax.collection.GraphEdge._
import scalax.collection.edge.WDiEdge
import scalax.collection.edge.Implicits._

case class Item(name: String)

class ThatSpec extends AnyFlatSpec with should.Matchers {
  "Graph API" should "be able to create simple undirected graphs" in {
    val g1 = Graph(1 ~ 3, 5)
    g1.edges.size shouldBe 1
    g1.nodes.size shouldBe 3

    val g2 = Graph("A" ~ "B", "B" ~ "C", "A" ~ "D")
    g2.edges.size shouldBe 3
    g2.nodes.size shouldBe 4
  }

  it should "be able to create simple directed graphs" in {
    val wheel = Graph(
      Item("A") ~> Item("B"),
      Item("B") ~> Item("C"),
      Item("C") ~> Item("D"),
      Item("D") ~> Item("A")
    )
    wheel.edges.size shouldBe 4
    wheel.nodes.size shouldBe 4 // and not 5 of course
  }

  it should "be able to create weighted directed/undirected graphs" in {
    // https://www.scala-graph.org/guides/core-traversing.html
    val graph = Graph(
        1 ~ 2  % 4,
        2 ~ 3  % 2,
        1 ~> 3 % 5,
        1 ~ 5  % 3,
        3 ~ 5  % 2,
        3 ~ 4  % 1,
        4 ~> 4 % 1,
        4 ~> 5 % 0
      )
    val sp0   = graph.get(3) shortestPathTo graph.get(1)
  }

  // TODO - to be continued...
}

org.scalatest.tools.Runner.main(Array("-oDF", "-s", classOf[ThatSpec].getName))