Scala Game of Life - Craftsmanship Guild Mini Coderetreat

GOLTest.scala

package guild.gameoflife

import org.scalatest.matchers.ShouldMatchers
import org.scalatest.prop.Checkers
import org.scalatest.Spec
import org.scalatest.junit.JUnitRunner
import org.junit.runner.RunWith

@RunWith(classOf[JUnitRunner])
class GOLTest extends Spec with ShouldMatchers with Checkers {

  describe("a Generation") {

    case class Coordinate(x: Int, y: Int)

    class Generation(cells: Set[Coordinate]) {
      def livingAt(location: Coordinate):Boolean = {
        cells.contains( location )
      }

      def evolve: Generation = {
        new Generation(cells.filter { us =>
          val neighborhood = for {
            x <- -1 to 1
            y <- -1 to 1
          } yield Coordinate(us.x + x, us.y + y)

          val n = (cells & neighborhood.toSet).size - 1

          n == 3
        })
      }
    }

    describe("with live cells") {
      val cells = Set(Coordinate(0, 0))
      val current = new Generation(cells)

      it("has a living cell") {
        current.livingAt(Coordinate(0,0)) should be (true)
      }

      it( "kills a cell with no neighbors")  {
        val next = current.evolve
        next.livingAt(Coordinate(0,0)) should be (false)
      }

      it("cells in a 2x2 block will continue to live ") {

        val cells = Set( Coordinate(0,0), Coordinate(1,0), Coordinate(0,1), Coordinate(1,1) )
        val next = new Generation( cells ).evolve
        next.livingAt( Coordinate(0,0) ) should be (true)
        next.livingAt( Coordinate(0,1) ) should be (true)
        next.livingAt( Coordinate(1,0) ) should be (true)
        next.livingAt( Coordinate(1,1) ) should be (true)

      }
    }


  }

}

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>guild</groupId>
  <artifactId>gameoflife-i1</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <name>gol-i1</name>
  <properties>
    <scala.version>2.9.0</scala.version>
  </properties>

  <repositories>
    <repository>
      <id>scala-tools.org</id>
      <name>Scala-Tools Maven2 Repository</name>
      <url>http://scala-tools.org/repo-releases</url>
    </repository>
  </repositories>

  <pluginRepositories>
    <pluginRepository>
      <id>scala-tools.org</id>
      <name>Scala-Tools Maven2 Repository</name>
      <url>http://scala-tools.org/repo-releases</url>
    </pluginRepository>
  </pluginRepositories>

  <dependencies>
    <dependency>
      <groupId>org.scala-lang</groupId>
      <artifactId>scala-library</artifactId>
      <version>${scala.version}</version>
    </dependency>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.4</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>org.scalatest</groupId>
      <artifactId>scalatest_2.9.0</artifactId>
      <version>1.4.1</version>
      <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.scala-tools.testing</groupId>
        <artifactId>scalacheck_2.9.0</artifactId>
        <version>1.8</version>
    </dependency>
  </dependencies>

  <build>
    <sourceDirectory>src/main/scala</sourceDirectory>
    <testSourceDirectory>src/test/scala</testSourceDirectory>
    <plugins>
      <plugin>
        <groupId>org.scala-tools</groupId>
        <artifactId>maven-scala-plugin</artifactId>
        <executions>
          <execution>
            <goals>
              <goal>compile</goal>
              <goal>testCompile</goal>
            </goals>
          </execution>
        </executions>
        <configuration>
          <scalaVersion>${scala.version}</scalaVersion>
          <args>
            <arg>-target:jvm-1.5</arg>
          </args>
        </configuration>
      </plugin>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-eclipse-plugin</artifactId>
        <configuration>
          <downloadSources>true</downloadSources>
          <buildcommands>
            <buildcommand>ch.epfl.lamp.sdt.core.scalabuilder</buildcommand>
          </buildcommands>
          <additionalProjectnatures>
            <projectnature>ch.epfl.lamp.sdt.core.scalanature</projectnature>
          </additionalProjectnatures>
          <classpathContainers>
            <classpathContainer>org.eclipse.jdt.launching.JRE_CONTAINER</classpathContainer>
            <classpathContainer>ch.epfl.lamp.sdt.launching.SCALA_CONTAINER</classpathContainer>
          </classpathContainers>
        </configuration>
      </plugin>
    </plugins>
  </build>
  <reporting>
    <plugins>
      <plugin>
        <groupId>org.scala-tools</groupId>
        <artifactId>maven-scala-plugin</artifactId>
        <configuration>
          <scalaVersion>${scala.version}</scalaVersion>
        </configuration>
      </plugin>
    </plugins>
  </reporting>
</project>