diff --git a/build.sbt b/build.sbt
index 33ed0cb..0f4ad5c 100644
--- a/build.sbt
+++ b/build.sbt
@@ -4,7 +4,7 @@ organization := "com.github.mdr"
 
 version := "0.0.6"
 
-scalaVersion := "2.10.1"
+scalaVersion := "2.12.1"
 
 crossScalaVersions := Seq("2.9.1", "2.9.2", "2.10.1")
 
@@ -12,9 +12,9 @@ scalacOptions ++= Seq("-deprecation")
 
 javacOptions ++= Seq("-source", "1.6", "-target", "1.6")
 
-libraryDependencies += "org.scalatest" %% "scalatest" % "1.9.1" % "test"
+libraryDependencies += "org.scalatest" %% "scalatest" % "3.0.1" % "test"
 
-libraryDependencies += "org.scalacheck" %% "scalacheck" % "1.10.1" % "test"
+libraryDependencies += "org.scalacheck" %% "scalacheck" % "1.13.4" % "test"
 
 // Screen-sized dependency graph:
 // libraryDependencies += "org.vert-x" % "vertx-core" % "1.3.1.final"
@@ -23,12 +23,12 @@ EclipseKeys.withSource := true
 
 EclipseKeys.eclipseOutput := Some("bin")
 
-net.virtualvoid.sbt.graph.Plugin.graphSettings
+//net.virtualvoid.sbt.graph.Plugin.graphSettings
 
-scalariformSettings
+import com.typesafe.sbt.SbtScalariform.ScalariformKeys
 
 ScalariformKeys.preferences <<= baseDirectory.apply { dir => 
-    scalariform.formatter.preferences.PreferencesImporterExporter.loadPreferences((dir / "formatterPreferences.properties").getPath)
+  scalariform.formatter.preferences.PreferencesImporterExporter.loadPreferences((dir / "formatterPreferences.properties").getPath)
 }
 
 publishMavenStyle := true
diff --git a/project/build.properties b/project/build.properties
index 9b860e2..24be09b 100644
--- a/project/build.properties
+++ b/project/build.properties
@@ -1 +1,2 @@
-sbt.version=0.12.3
+sbt.version=0.13.13
+
diff --git a/project/plugins.sbt b/project/plugins.sbt
index 233bdbd..afe242f 100644
--- a/project/plugins.sbt
+++ b/project/plugins.sbt
@@ -1,11 +1,10 @@
 addSbtPlugin("com.typesafe.sbteclipse" % "sbteclipse-plugin" % "2.2.0")
 
-addSbtPlugin("net.virtual-void" % "sbt-dependency-graph" % "0.7.3")
-
-// addSbtPlugin("net.virtual-void" % "sbt-dependency-graph" % "0.7.4-SNAPSHOT")
+addSbtPlugin("net.virtual-void" % "sbt-dependency-graph" % "0.8.2")
 
 addSbtPlugin("com.typesafe.sbt" % "sbt-pgp" % "0.8")
 
-addSbtPlugin("com.github.mpeltonen" % "sbt-idea" % "1.4.0")
+resolvers += Resolver.typesafeRepo("releases")
+
+addSbtPlugin("org.scalariform" % "sbt-scalariform" % "1.6.0")
 
-addSbtPlugin("com.typesafe.sbt" % "sbt-scalariform" % "1.0.1")	
diff --git a/src/main/java/com/github/mdr/ascii/java/ScalaJavaHelper.scala b/src/main/java/com/github/mdr/ascii/java/ScalaJavaHelper.scala
index 4672e38..16afb6f 100644
--- a/src/main/java/com/github/mdr/ascii/java/ScalaJavaHelper.scala
+++ b/src/main/java/com/github/mdr/ascii/java/ScalaJavaHelper.scala
@@ -1,6 +1,6 @@
 package com.github.mdr.ascii.java
 
-import java.{ util ⇒ ju }
+import java.{util ⇒ ju}
 import scala.collection.JavaConverters._
 import com.github.mdr.ascii.graph.Graph
 import com.github.mdr.ascii.layout.GraphLayout
diff --git a/src/main/scala/com/github/mdr/ascii/diagram/Box.scala b/src/main/scala/com/github/mdr/ascii/diagram/Box.scala
index 91ab2c7..f5ab23e 100644
--- a/src/main/scala/com/github/mdr/ascii/diagram/Box.scala
+++ b/src/main/scala/com/github/mdr/ascii/diagram/Box.scala
@@ -15,6 +15,6 @@ trait Box extends Container {
       edge ← edges
       if edgeType.includeEdge(edge, this)
       otherBox = edge.otherBox(this)
-    } yield edge -> otherBox
+    } yield edge → otherBox
 
 }
diff --git a/src/main/scala/com/github/mdr/ascii/diagram/parser/DiagramImplementation.scala b/src/main/scala/com/github/mdr/ascii/diagram/parser/DiagramImplementation.scala
index ceaee2a..8d6c7f0 100644
--- a/src/main/scala/com/github/mdr/ascii/diagram/parser/DiagramImplementation.scala
+++ b/src/main/scala/com/github/mdr/ascii/diagram/parser/DiagramImplementation.scala
@@ -95,10 +95,13 @@ trait DiagramImplementation { self: DiagramParser ⇒
       Region(
         Point(
           points.map(_.row).min,
-          points.map(_.column).min),
+          points.map(_.column).min
+        ),
         Point(
           points.map(_.row).max,
-          points.map(_.column).max))
+          points.map(_.column).max
+        )
+      )
 
   }
 
diff --git a/src/main/scala/com/github/mdr/ascii/diagram/parser/DiagramParser.scala b/src/main/scala/com/github/mdr/ascii/diagram/parser/DiagramParser.scala
index 53e4f67..8c45611 100644
--- a/src/main/scala/com/github/mdr/ascii/diagram/parser/DiagramParser.scala
+++ b/src/main/scala/com/github/mdr/ascii/diagram/parser/DiagramParser.scala
@@ -35,7 +35,7 @@ class DiagramParser(s: String)
       innerBox ← diagram.allBoxes
       if outerBox != innerBox
       if outerBox.region contains innerBox.region
-    } yield outerBox -> innerBox).toMap
+    } yield outerBox → innerBox).toMap
 
   for {
     (box, containingBoxMap) ← boxContains.groupBy(_._2)
diff --git a/src/main/scala/com/github/mdr/ascii/graph/DiagramToGraphConverter.scala b/src/main/scala/com/github/mdr/ascii/graph/DiagramToGraphConverter.scala
index 6c0ec2f..5a3d9f1 100644
--- a/src/main/scala/com/github/mdr/ascii/graph/DiagramToGraphConverter.scala
+++ b/src/main/scala/com/github/mdr/ascii/graph/DiagramToGraphConverter.scala
@@ -17,9 +17,9 @@ object DiagramToGraphConvertor {
         vertex2 ← boxToVertexMap.get(edge.box2)
       } yield {
         if (edge.hasArrow2)
-          vertex1 -> vertex2
+          vertex1 → vertex2
         else
-          vertex2 -> vertex1
+          vertex2 → vertex1
       }
     Graph(vertices, edges)
   }
diff --git a/src/main/scala/com/github/mdr/ascii/layout/GraphLayout.scala b/src/main/scala/com/github/mdr/ascii/layout/GraphLayout.scala
index be73d04..24461d5 100644
--- a/src/main/scala/com/github/mdr/ascii/layout/GraphLayout.scala
+++ b/src/main/scala/com/github/mdr/ascii/layout/GraphLayout.scala
@@ -19,7 +19,8 @@ object GraphLayout {
   def renderGraph[V](
     graph: Graph[V],
     vertexRenderingStrategy: VertexRenderingStrategy[V] = ToStringVertexRenderingStrategy,
-    layoutPrefs: LayoutPrefs = LayoutPrefsImpl()): String = {
+    layoutPrefs: LayoutPrefs = LayoutPrefsImpl()
+  ): String = {
     val cycleRemovalResult = CycleRemover.removeCycles(graph)
     val (layering, _) = new LayeringCalculator[V].assignLayers(cycleRemovalResult)
     val reorderedLayering = LayerOrderingCalculator.reorder(layering)
@@ -30,12 +31,6 @@ object GraphLayout {
       drawing = KinkRemover.removeKinks(drawing)
     if (layoutPrefs.elevateEdges)
       drawing = EdgeElevator.elevateEdges(drawing)
-
-    //    if (layoutPrefs.removeKinks)
-    //      drawing = KinkRemover.removeKinks(drawing)
-    //    if (layoutPrefs.elevateEdges)
-    //      drawing = EdgeElevator.elevateEdges(drawing)
-    //
     if (layoutPrefs.compactify)
       drawing = RedundantRowRemover.removeRedundantRows(drawing)
 
diff --git a/src/main/scala/com/github/mdr/ascii/layout/coordAssign/EdgeBendCalculator.scala b/src/main/scala/com/github/mdr/ascii/layout/coordAssign/EdgeBendCalculator.scala
index b8609ef..a3522f5 100644
--- a/src/main/scala/com/github/mdr/ascii/layout/coordAssign/EdgeBendCalculator.scala
+++ b/src/main/scala/com/github/mdr/ascii/layout/coordAssign/EdgeBendCalculator.scala
@@ -90,8 +90,8 @@ class EdgeBendCalculator(edgeInfos: List[EdgeInfo], edgeZoneTopRow: Int, selfEdg
         if row1 > row2
         if !swappedEdges.contains((edgeInfo1, edgeInfo2)) // Prevents more involved infinite loops
       } {
-        updatedEdgeToRowMap += edgeInfo1 -> row2
-        updatedEdgeToRowMap += edgeInfo2 -> row1
+        updatedEdgeToRowMap += edgeInfo1 → row2
+        updatedEdgeToRowMap += edgeInfo2 → row1
         swappedEdges += ((edgeInfo1, edgeInfo2))
         continue = true
       }
diff --git a/src/main/scala/com/github/mdr/ascii/layout/coordAssign/Layouter.scala b/src/main/scala/com/github/mdr/ascii/layout/coordAssign/Layouter.scala
index c75b7d1..61c0298 100644
--- a/src/main/scala/com/github/mdr/ascii/layout/coordAssign/Layouter.scala
+++ b/src/main/scala/com/github/mdr/ascii/layout/coordAssign/Layouter.scala
@@ -45,7 +45,7 @@ class Layouter(vertexRenderingStrategy: VertexRenderingStrategy[_], vertical: Bo
     var layerInfos: Map[Layer, LayerInfo] = Map()
     for ((previousLayerOpt, currentLayer, nextLayerOpt) ← Utils.withPreviousAndNext(layering.layers)) {
       val layerInfo = calculateLayerInfo(currentLayer, layering.edges, previousLayerOpt, nextLayerOpt)
-      layerInfos += currentLayer -> layerInfo
+      layerInfos += currentLayer → layerInfo
     }
     PortNudger.nudge(layering, spaceVertices(layerInfos))
   }
@@ -99,8 +99,8 @@ class Layouter(vertexRenderingStrategy: VertexRenderingStrategy[_], vertical: Bo
   private def makeVertexInfo(vertex: DummyVertex, boxRegion: Region, greaterRegion: Region, inEdges: List[Edge], outEdges: List[Edge]): VertexInfo = {
     val (List(inVertex), List(outVertex)) = (inEdges, outEdges)
     val port = boxRegion.topLeft
-    val inEdgeToPortMap = Map(inVertex -> port)
-    val outEdgeToPortMap = Map(outVertex -> port)
+    val inEdgeToPortMap = Map(inVertex → port)
+    val outEdgeToPortMap = Map(outVertex → port)
     VertexInfo(boxRegion, greaterRegion, inEdgeToPortMap, outEdgeToPortMap, Nil, Nil)
   }
 
@@ -164,7 +164,7 @@ class Layouter(vertexRenderingStrategy: VertexRenderingStrategy[_], vertical: Bo
         case _                                                  ⇒ 0
       }
       val greaterRegion = boxRegion.expandRight(selfEdgesSpacing).expandUp(selfEdgesSpacing).expandDown(selfEdgesSpacing)
-      regions += vertex -> (boxRegion, greaterRegion)
+      regions += vertex → (boxRegion, greaterRegion)
       nextVertexTopLeft = boxRegion.topRight.right(selfEdgesSpacing + 2)
     }
     regions
@@ -185,7 +185,7 @@ class Layouter(vertexRenderingStrategy: VertexRenderingStrategy[_], vertical: Bo
 
   private def spaceVertices(layerInfos: Map[Layer, LayerInfo]): Map[Layer, LayerInfo] = {
     val diagramWidth = calculateDiagramWidth(layerInfos)
-    layerInfos.map { case (layer, info) ⇒ layer -> spaceVertices(layer, info, diagramWidth) }
+    layerInfos.map { case (layer, info) ⇒ layer → spaceVertices(layer, info, diagramWidth) }
   }
 
   /**
@@ -209,7 +209,7 @@ class Layouter(vertexRenderingStrategy: VertexRenderingStrategy[_], vertical: Bo
         leftColumn += vertexInfo.greaterRegion.width
         leftColumn += horizontalSpacing
         val verticalCenteringOffset = (layerHeight - vertexInfo.boxRegion.height) / 2
-        v -> vertexInfo.setLeft(oldLeftColumn).down(verticalCenteringOffset)
+        v → vertexInfo.setLeft(oldLeftColumn).down(verticalCenteringOffset)
       }
     LayerInfo(newVertexInfos.toMap)
   }
@@ -217,7 +217,8 @@ class Layouter(vertexRenderingStrategy: VertexRenderingStrategy[_], vertical: Bo
   private case class LayerLayoutResult(
     drawingElements: List[DrawingElement],
     layerInfo: LayerInfo,
-    updatedIncompletedEdges: Map[DummyVertex, List[Point]])
+    updatedIncompletedEdges: Map[DummyVertex, List[Point]]
+  )
 
   /**
    * 1) Decide the (vertical) order of edges coming into the currentLayer -- that is, what row they bend on (if required)
@@ -233,7 +234,8 @@ class Layouter(vertexRenderingStrategy: VertexRenderingStrategy[_], vertical: Bo
     previousLayerInfo: LayerInfo,
     currentLayerInfo: LayerInfo,
     edges: List[Edge],
-    incompleteEdges: Map[DummyVertex, List[Point]]): LayerLayoutResult = {
+    incompleteEdges: Map[DummyVertex, List[Point]]
+  ): LayerLayoutResult = {
 
     val edgeInfos: List[EdgeInfo] = makeEdgeInfos(edges, previousLayerInfo, currentLayerInfo)
 
@@ -245,7 +247,7 @@ class Layouter(vertexRenderingStrategy: VertexRenderingStrategy[_], vertical: Bo
 
     val updatedIncompleteEdges: Map[DummyVertex, List[Point]] =
       for ((EdgeInfo(_, finishVertex: DummyVertex, _, _, _), points) ← edgeInfoToPoints)
-        yield finishVertex -> points
+        yield finishVertex → points
 
     val updatedLayerInfo = currentLayerInfo.down(edgeBendCalculator.edgeZoneBottomRow + 1)
 
@@ -317,7 +319,7 @@ class Layouter(vertexRenderingStrategy: VertexRenderingStrategy[_], vertical: Bo
     val p4 = p3.up(vertexInfo.boxRegion.height + 2 * (selfEdgeIndex + 1) + 1)
     val p5 = p4.left(p4.column - inPort.column)
     val p6 = inPort.up(1)
-    EdgeDrawingElement(List(p1, p2, p3, p4, p5, p6), false, true)
+    EdgeDrawingElement(List(p1, p2, p3, p4, p5, p6), hasArrow1 = false, hasArrow2 = true)
   }
 
   private def makeVertexElements(layerInfo: LayerInfo): List[VertexDrawingElement] =
diff --git a/src/main/scala/com/github/mdr/ascii/layout/coordAssign/PortNudger.scala b/src/main/scala/com/github/mdr/ascii/layout/coordAssign/PortNudger.scala
index 7c9f345..fceac37 100644
--- a/src/main/scala/com/github/mdr/ascii/layout/coordAssign/PortNudger.scala
+++ b/src/main/scala/com/github/mdr/ascii/layout/coordAssign/PortNudger.scala
@@ -36,7 +36,7 @@ object PortNudger {
       val previousLayerInfoOpt = previousLayerOpt.map(updatedLayerInfos)
       val currentLayerInfo = layerInfos(currentLayer)
       val updatedLayerInfo = nudgeLayer(previousLayerInfoOpt, currentLayerInfo)
-      updatedLayerInfos += currentLayer -> updatedLayerInfo
+      updatedLayerInfos += currentLayer → updatedLayerInfo
     }
     updatedLayerInfos
   }
@@ -53,7 +53,7 @@ object PortNudger {
 
     val newVertexInfos = currentLayerInfo.vertexInfos.map {
       case (vertex, vertexInfo) ⇒
-        vertex -> nudgeVertexInfo(vertex, vertexInfo, previousLayerInfoOpt, previousEdgeColumns)
+        vertex → nudgeVertexInfo(vertex, vertexInfo, previousLayerInfoOpt, previousEdgeColumns)
     }
     currentLayerInfo.copy(vertexInfos = newVertexInfos)
   }
@@ -67,14 +67,14 @@ object PortNudger {
     val newInEdgeToPortMap = vertexInfo.inEdgeToPortMap.map {
       case (edge, port) if shouldNudge(edge, port) ⇒
         nudgedColumns += port.column
-        edge -> port.right
+        edge → port.right
       case pair ⇒ pair
     }
 
     // We need to also nudge the out ports for dummy vertices we nudged earlier
     val newOutEdgeToPortMap = vertex match {
       case _: DummyVertex ⇒ vertexInfo.outEdgeToPortMap.map {
-        case (edge, port) if nudgedColumns contains port.column ⇒ edge -> port.right
+        case (edge, port) if nudgedColumns contains port.column ⇒ edge → port.right
         case pair                                               ⇒ pair
       }
       case _: RealVertex ⇒ vertexInfo.outEdgeToPortMap
diff --git a/src/main/scala/com/github/mdr/ascii/layout/coordAssign/VertexInfo.scala b/src/main/scala/com/github/mdr/ascii/layout/coordAssign/VertexInfo.scala
index 2c72a4f..2b13009 100644
--- a/src/main/scala/com/github/mdr/ascii/layout/coordAssign/VertexInfo.scala
+++ b/src/main/scala/com/github/mdr/ascii/layout/coordAssign/VertexInfo.scala
@@ -20,7 +20,8 @@ case class VertexInfo(
   inEdgeToPortMap: Map[Edge, Point],
   outEdgeToPortMap: Map[Edge, Point],
   selfInPorts: List[Point],
-  selfOutPorts: List[Point])
+  selfOutPorts: List[Point]
+)
     extends Translatable[VertexInfo] {
 
   /**
@@ -35,7 +36,8 @@ case class VertexInfo(
       Utils.transformValues(inEdgeToPortMap)(_.translate(down, right)),
       Utils.transformValues(outEdgeToPortMap)(_.translate(down, right)),
       selfInPorts.map(_.translate(down, right)),
-      selfOutPorts.map(_.translate(down, right)))
+      selfOutPorts.map(_.translate(down, right))
+    )
 
   def setLeft(column: Int): VertexInfo = translate(right = column - boxRegion.leftColumn)
 
diff --git a/src/main/scala/com/github/mdr/ascii/layout/cycles/CycleRemovalInfo.scala b/src/main/scala/com/github/mdr/ascii/layout/cycles/CycleRemovalInfo.scala
index 199fbda..6cc9efc 100644
--- a/src/main/scala/com/github/mdr/ascii/layout/cycles/CycleRemovalInfo.scala
+++ b/src/main/scala/com/github/mdr/ascii/layout/cycles/CycleRemovalInfo.scala
@@ -68,8 +68,8 @@ class CycleRemovalInfo[V](graph: Graph[V]) {
   }
 
   private def addVertexToDegreeDiffMaps(v: V, degreeDiff: Int) = {
-    degreeDiffToVertices += degreeDiff -> (v :: degreeDiffToVertices.getOrElse(degreeDiff, Nil))
-    verticesToDegreeDiff += v -> degreeDiff
+    degreeDiffToVertices += degreeDiff → (v :: degreeDiffToVertices.getOrElse(degreeDiff, Nil))
+    verticesToDegreeDiff += v → degreeDiff
   }
 
   private def removeVertexFromDegreeDiffMaps(v: V): Int = {
@@ -79,7 +79,7 @@ class CycleRemovalInfo[V](graph: Graph[V]) {
     if (updatedVertices.isEmpty)
       degreeDiffToVertices -= degreeDiff
     else
-      degreeDiffToVertices += degreeDiff -> updatedVertices
+      degreeDiffToVertices += degreeDiff → updatedVertices
     verticesToDegreeDiff -= v
     degreeDiff
   }
diff --git a/src/main/scala/com/github/mdr/ascii/layout/drawing/DrawingElement.scala b/src/main/scala/com/github/mdr/ascii/layout/drawing/DrawingElement.scala
index 96adab4..39655c3 100644
--- a/src/main/scala/com/github/mdr/ascii/layout/drawing/DrawingElement.scala
+++ b/src/main/scala/com/github/mdr/ascii/layout/drawing/DrawingElement.scala
@@ -50,7 +50,8 @@ case class VertexDrawingElement(region: Region, textLines: List[String])
 case class EdgeDrawingElement(
   bendPoints: List[Point],
   hasArrow1: Boolean,
-  hasArrow2: Boolean)
+  hasArrow2: Boolean
+)
     extends DrawingElement with Translatable[EdgeDrawingElement] with Transposable[EdgeDrawingElement] {
 
   lazy val points: List[Point] = segments.flatMap(_.points).distinct
diff --git a/src/main/scala/com/github/mdr/ascii/layout/drawing/EdgeElevator.scala b/src/main/scala/com/github/mdr/ascii/layout/drawing/EdgeElevator.scala
index f186103..d6f218c 100644
--- a/src/main/scala/com/github/mdr/ascii/layout/drawing/EdgeElevator.scala
+++ b/src/main/scala/com/github/mdr/ascii/layout/drawing/EdgeElevator.scala
@@ -38,7 +38,7 @@ object EdgeElevator {
     for {
       segmentInfo ← segmentInfos.sortBy(_.row)
       updatedEdgeSegment ← elevate(segmentInfo, edgeTracker)
-    } segmentUpdates = addToMultimap(segmentUpdates, segmentInfo.edgeElement, segmentInfo.segment2 -> updatedEdgeSegment)
+    } segmentUpdates = addToMultimap(segmentUpdates, segmentInfo.edgeElement, segmentInfo.segment2 → updatedEdgeSegment)
 
     for ((edge, updates) ← segmentUpdates)
       currentDrawing = currentDrawing.replaceElement(edge, updateEdge(edge, updates))
diff --git a/src/main/scala/com/github/mdr/ascii/layout/drawing/EdgeSegmentInfo.scala b/src/main/scala/com/github/mdr/ascii/layout/drawing/EdgeSegmentInfo.scala
index 03cdcb0..becc249 100644
--- a/src/main/scala/com/github/mdr/ascii/layout/drawing/EdgeSegmentInfo.scala
+++ b/src/main/scala/com/github/mdr/ascii/layout/drawing/EdgeSegmentInfo.scala
@@ -11,7 +11,8 @@ package com.github.mdr.ascii.layout.drawing
  *                   v
  */
 case class EdgeSegmentInfo(
-    edgeElement: EdgeDrawingElement, segment1: EdgeSegment, segment2: EdgeSegment, segment3: EdgeSegment) {
+    edgeElement: EdgeDrawingElement, segment1: EdgeSegment, segment2: EdgeSegment, segment3: EdgeSegment
+) {
 
   def row = segment2.start.row
 
diff --git a/src/main/scala/com/github/mdr/ascii/layout/drawing/KinkRemover.scala b/src/main/scala/com/github/mdr/ascii/layout/drawing/KinkRemover.scala
index fc5612b..3435ca5 100644
--- a/src/main/scala/com/github/mdr/ascii/layout/drawing/KinkRemover.scala
+++ b/src/main/scala/com/github/mdr/ascii/layout/drawing/KinkRemover.scala
@@ -40,7 +40,7 @@ object KinkRemover {
     for {
       edgeElement ← drawing.edgeElements
       newEdgeElement ← removeKink(edgeElement, drawing, edgeTracker)
-    } return Some(edgeElement -> newEdgeElement)
+    } return Some(edgeElement → newEdgeElement)
     None
   }
 
diff --git a/src/main/scala/com/github/mdr/ascii/layout/layering/LayeringCalculator.scala b/src/main/scala/com/github/mdr/ascii/layout/layering/LayeringCalculator.scala
index 95b6a93..cd199c2 100644
--- a/src/main/scala/com/github/mdr/ascii/layout/layering/LayeringCalculator.scala
+++ b/src/main/scala/com/github/mdr/ascii/layout/layering/LayeringCalculator.scala
@@ -70,7 +70,7 @@ class LayeringCalculator[V] {
           if (count == 1)
             revEdges -= graphEdge
           else
-            revEdges += graphEdge -> (count - 1)
+            revEdges += graphEdge → (count - 1)
           true
         case None ⇒
           false
@@ -83,7 +83,7 @@ class LayeringCalculator[V] {
   private def makeRealVertices(cycleRemovalResult: CycleRemovalResult[V]): Map[V, RealVertex] =
     cycleRemovalResult.dag.vertices.map { v ⇒
       val selfEdges = cycleRemovalResult.countSelfEdges(v)
-      v -> new RealVertex(v, selfEdges)
+      v → new RealVertex(v, selfEdges)
     }.toMap
 
 }
\ No newline at end of file
diff --git a/src/main/scala/com/github/mdr/ascii/layout/layering/LongestDistancesToSinkCalculator.scala b/src/main/scala/com/github/mdr/ascii/layout/layering/LongestDistancesToSinkCalculator.scala
index 04d0517..ac061ea 100644
--- a/src/main/scala/com/github/mdr/ascii/layout/layering/LongestDistancesToSinkCalculator.scala
+++ b/src/main/scala/com/github/mdr/ascii/layout/layering/LongestDistancesToSinkCalculator.scala
@@ -20,7 +20,7 @@ object LongestDistancesToSinkCalculator {
     /**
      * The current known longest distances to a sink.
      */
-    var distances: Map[V, Int] = graph.vertices.map(_ -> 0).toMap
+    var distances: Map[V, Int] = graph.vertices.map(_ → 0).toMap
 
     var boundary = finalisedVertices
 
@@ -31,7 +31,7 @@ object LongestDistancesToSinkCalculator {
         v1 ← graph.inVertices(v2)
       } {
         val newDistance = math.max(distances(v1), distances(v2) + 1)
-        distances += v1 -> newDistance
+        distances += v1 → newDistance
         if (graph.outVertices(v1).forall(finalisedVertices)) {
           finalisedVertices += v1
           newBoundary += v1
diff --git a/src/main/scala/com/github/mdr/ascii/layout/prefs/LayoutPrefsImpl.scala b/src/main/scala/com/github/mdr/ascii/layout/prefs/LayoutPrefsImpl.scala
index e53563e..ca30476 100644
--- a/src/main/scala/com/github/mdr/ascii/layout/prefs/LayoutPrefsImpl.scala
+++ b/src/main/scala/com/github/mdr/ascii/layout/prefs/LayoutPrefsImpl.scala
@@ -17,5 +17,6 @@ case class LayoutPrefsImpl(
   unicode: Boolean = true,
   doubleVertices: Boolean = false,
   rounded: Boolean = false, // Typical Windows fonts don't render bend characters correctly
-  explicitAsciiBends: Boolean = false)
+  explicitAsciiBends: Boolean = false
+)
     extends LayoutPrefs
diff --git a/src/main/scala/com/github/mdr/ascii/util/QuadTree.scala b/src/main/scala/com/github/mdr/ascii/util/QuadTree.scala
index 07c56b8..589859a 100644
--- a/src/main/scala/com/github/mdr/ascii/util/QuadTree.scala
+++ b/src/main/scala/com/github/mdr/ascii/util/QuadTree.scala
@@ -33,7 +33,8 @@ class QuadTree[T <: HasRegion](dimension: Dimension) {
   }
 
   private case class QuadNode(
-    region: Region, items: Set[T], topLeft: Node, topRight: Node, bottomLeft: Node, bottomRight: Node)
+    region: Region, items: Set[T], topLeft: Node, topRight: Node, bottomLeft: Node, bottomRight: Node
+  )
       extends Node {
 
     override def childNodes: List[Node] = List(topLeft, topRight, bottomLeft, bottomRight)
diff --git a/src/main/scala/com/github/mdr/ascii/util/Utils.scala b/src/main/scala/com/github/mdr/ascii/util/Utils.scala
index 4a1c23e..afef559 100644
--- a/src/main/scala/com/github/mdr/ascii/util/Utils.scala
+++ b/src/main/scala/com/github/mdr/ascii/util/Utils.scala
@@ -44,7 +44,7 @@ object Utils {
   }
 
   def makeMap[T, U](s: Iterable[T], f: T ⇒ U): Map[T, U] =
-    s.map(t ⇒ t -> f(t))(collection.breakOut)
+    s.map(t ⇒ t → f(t))(collection.breakOut)
 
   def signum(x: Int) = x match {
     case _ if x < 0 ⇒ -1
@@ -64,6 +64,6 @@ object Utils {
     xs.map { t ⇒ if (fn isDefinedAt t) fn(t) else t }
 
   def addToMultimap[K, V](m: Map[K, List[V]], k: K, v: V): Map[K, List[V]] =
-    m + (k -> (v :: m.getOrElse(k, Nil)))
+    m + (k → (v :: m.getOrElse(k, Nil)))
 
 }
\ No newline at end of file
diff --git a/src/test/scala/com/github/mdr/ascii/RunLayout.scala b/src/test/scala/com/github/mdr/ascii/RunLayout.scala
index a0abc88..7cd0906 100644
--- a/src/test/scala/com/github/mdr/ascii/RunLayout.scala
+++ b/src/test/scala/com/github/mdr/ascii/RunLayout.scala
@@ -18,16 +18,19 @@ object RunLayout extends App {
 
   val graph1 = Graph(
     vertices = Set(
-      1, 2, 3, 4, 5, 6, 7, 8123, 9, 120),
+      1, 2, 3, 4, 5, 6, 7, 8123, 9, 120
+    ),
     edges = List(
-      1 -> 3,
-      1 -> 4,
-      3 -> 8123,
-      2 -> 5,
-      2 -> 6,
-      3 -> 7,
-      5 -> 9,
-      7 -> 9))
+      1 → 3,
+      1 → 4,
+      3 → 8123,
+      2 → 5,
+      2 → 6,
+      3 → 7,
+      5 → 9,
+      7 → 9
+    )
+  )
 
   val V1 = "111111"
   val V2 = "22222222"
@@ -39,16 +42,19 @@ object RunLayout extends App {
 
   val graph2 = Graph(
     vertices = Set(
-      V1, V2, V3, V4, V5, V6, V7),
+      V1, V2, V3, V4, V5, V6, V7
+    ),
     edges = List(
-      V1 -> V2,
-      V7 -> V1,
-      V1 -> V3,
-      V1 -> V4,
-      V2 -> V5,
-      V2 -> V6,
-      V6 -> V1,
-      V3 -> V7))
+      V1 → V2,
+      V7 → V1,
+      V1 → V3,
+      V1 → V4,
+      V2 → V5,
+      V2 → V6,
+      V6 → V1,
+      V3 → V7
+    )
+  )
 
   val graph3 = Graph.fromDiagram(
     """
@@ -108,7 +114,8 @@ object RunLayout extends App {
   |org.apache.geronimo.specs| |org.apache.lucene| |org.scala-lang|    
   |          1.1.1          | |      3.5.0      | |    2.9.1     |    
   +-------------------------+ +-----------------+ +--------------+    
-""")
+"""
+  )
 
   val v1 = """Person
              |────────────
@@ -123,7 +130,7 @@ object RunLayout extends App {
               |name = "Thingies Ltd"
               |employees = 123""".stripMargin
   val vertices4 = Set(v1, v2, v3)
-  val edges4 = List(v1 -> v2, v3 -> v1, v3 -> v2)
+  val edges4 = List(v1 → v2, v3 → v1, v3 → v2)
 
   val graph4 = Graph(vertices4, edges4)
 
diff --git a/src/test/scala/com/github/mdr/ascii/diagram/parser/DiagramParserTest.scala b/src/test/scala/com/github/mdr/ascii/diagram/parser/DiagramParserTest.scala
index ddc5875..04f3ccb 100644
--- a/src/test/scala/com/github/mdr/ascii/diagram/parser/DiagramParserTest.scala
+++ b/src/test/scala/com/github/mdr/ascii/diagram/parser/DiagramParserTest.scala
@@ -1,13 +1,13 @@
 package com.github.mdr.ascii.diagram.parser
 
-import org.scalatest.matchers.ShouldMatchers
-import org.scalatest.FlatSpec
+import org.scalatest.{FlatSpec, Matchers}
 import com.github.mdr.ascii.diagram.Diagram
 import com.github.mdr.ascii.diagram.Box
 import com.github.mdr.ascii.util.Utils
+
 import scala.io.Source
 
-class GraphDiagramParserTest extends FlatSpec with ShouldMatchers {
+class GraphDiagramParserTest extends FlatSpec with Matchers {
 
   "Parser" should "parse labels" in {
 
@@ -47,7 +47,7 @@ class GraphDiagramParserTest extends FlatSpec with ShouldMatchers {
             |C| |D|  
             +-+ +-+
     """)
-    checkEdges(diagram, "A" -> "D", "B" -> "C")
+    checkEdges(diagram, "A" → "D", "B" → "C")
   }
 
   it should "support Unicode box-drawing characters" in {
@@ -65,7 +65,7 @@ class GraphDiagramParserTest extends FlatSpec with ShouldMatchers {
      ╰───╯ ╰───╯""")
 
     diagram.allBoxes.map(text).toSet should equal(Set("A", "B", "C"))
-    checkEdges(diagram, "A" -> "B", "A" -> "C")
+    checkEdges(diagram, "A" → "B", "A" → "C")
   }
 
   it should "support Unicode box-drawing characters 2" in {
@@ -79,7 +79,7 @@ class GraphDiagramParserTest extends FlatSpec with ShouldMatchers {
                ╰─>│fb│
                   ╰──╯
        """)
-    checkEdges(diagram, "feadda" -> "ee", "feadda" -> "db\nfb")
+    checkEdges(diagram, "feadda" → "ee", "feadda" → "db\nfb")
   }
 
   it should "support Unicode box-drawing characters 3" in {
@@ -93,7 +93,7 @@ class GraphDiagramParserTest extends FlatSpec with ShouldMatchers {
      ╰──────╯
         
        """)
-    checkEdges(diagram, "foobar" -> "xx", "foobar" -> "yy")
+    checkEdges(diagram, "foobar" → "xx", "foobar" → "yy")
   }
 
   it should "parse an empty box" in {
@@ -113,7 +113,7 @@ class GraphDiagramParserTest extends FlatSpec with ShouldMatchers {
      ╰─╯╰─╯
     """)
     diagram.allBoxes.map(text).toSet should equal(Set("A", "B"))
-    checkEdges(diagram, "A" -> "B")
+    checkEdges(diagram, "A" → "B")
   }
 
   it should "not find an edge between adjacent connected boxes (ASCII)" in {
@@ -133,7 +133,7 @@ class GraphDiagramParserTest extends FlatSpec with ShouldMatchers {
      │foobar├──╯   │yyy│              
      ╰──────╯      ╰───╯
        """)
-    checkEdges(diagram, "foobar" -> "yyy")
+    checkEdges(diagram, "foobar" → "yyy")
   }
 
   it should "handle misc arrows" in {
@@ -154,15 +154,17 @@ class GraphDiagramParserTest extends FlatSpec with ShouldMatchers {
                │      │            ╰────┤  │    
                ╰──────╯                 ╰──╯    
    """)
-    checkEdges(diagram,
-      "AA" -> "FF",
-      "AA" -> "D",
-      "BB" -> "AA",
-      "BB" -> "EE",
-      "CC" -> "D",
-      "D" -> "BB",
-      "D" -> "EE",
-      "EE" -> "D")
+    checkEdges(
+      diagram,
+      "AA" → "FF",
+      "AA" → "D",
+      "BB" → "AA",
+      "BB" → "EE",
+      "CC" → "D",
+      "D" → "BB",
+      "D" → "EE",
+      "EE" → "D"
+    )
 
   }
 
@@ -192,14 +194,16 @@ class GraphDiagramParserTest extends FlatSpec with ShouldMatchers {
         │  N  │     
         └─────┘     
         """)
-    checkEdges(diagram,
-      "P" -> "T",
-      "P" -> "O",
-      "P" -> "N",
-      "T" -> "O",
-      "H" -> "T",
-      "T" -> "O",
-      "O" -> "N")
+    checkEdges(
+      diagram,
+      "P" → "T",
+      "P" → "O",
+      "P" → "N",
+      "T" → "O",
+      "H" → "T",
+      "T" → "O",
+      "O" → "N"
+    )
   }
 
   it should "support ASCII edge bend characters" in {
@@ -213,7 +217,7 @@ class GraphDiagramParserTest extends FlatSpec with ShouldMatchers {
     | |-----/           
     +-+             
        """)
-    checkEdges(diagram, "I" -> "H", "H" -> "D", "I" -> "D")
+    checkEdges(diagram, "I" → "H", "H" → "D", "I" → "D")
   }
 
   it should "support ASCII edge bend characters 2" in {
@@ -236,7 +240,7 @@ class GraphDiagramParserTest extends FlatSpec with ShouldMatchers {
          | |        
          +-+
     """)
-    checkEdges(diagram, "A" -> "D", "E" -> "W", "D" -> "A", "A" -> "M", "A" -> "M", "M" -> "W")
+    checkEdges(diagram, "A" → "D", "E" → "W", "D" → "A", "A" → "M", "A" → "M", "M" → "W")
   }
 
   it should "support ASCII edge bend characters 3" in {
@@ -259,13 +263,13 @@ class GraphDiagramParserTest extends FlatSpec with ShouldMatchers {
                       |S|
                       +-+
          """)
-    checkEdges(diagram, "F" -> "L",
-      "J" -> "K",
-      "L" -> "K",
-      "K" -> "J",
-      "F" -> "K",
-      "J" -> "F",
-      "K" -> "L")
+    checkEdges(diagram, "F" → "L",
+      "J" → "K",
+      "L" → "K",
+      "K" → "J",
+      "F" → "K",
+      "J" → "F",
+      "K" → "L")
   }
 
   it should "support ASCII edge bend characters 4" in {
@@ -286,10 +290,12 @@ class GraphDiagramParserTest extends FlatSpec with ShouldMatchers {
       |  C  | |  H  |    
       +-----+ +-----+    
     """)
-    checkEdges(diagram,
-      "R" -> "C",
-      "I" -> "H",
-      "D" -> "H")
+    checkEdges(
+      diagram,
+      "R" → "C",
+      "I" → "H",
+      "D" → "H"
+    )
   }
 
   it should "Parse double-edged boxes" in {
@@ -309,7 +315,7 @@ class GraphDiagramParserTest extends FlatSpec with ShouldMatchers {
   }
 
   private def checkEdges(diagram: Diagram, expectedEdges: (String, String)*) {
-    val edges = diagram.allEdges.map(e ⇒ text(e.box1) -> text(e.box2))
+    val edges = diagram.allEdges.map(e ⇒ text(e.box1) → text(e.box2))
     edges.toSet should equal(expectedEdges.toSet)
     Utils.multisetCompare(edges, expectedEdges.toList) should be(true)
   }
diff --git a/src/test/scala/com/github/mdr/ascii/diagram/parser/Issue1DirectedEdgeNotParsedTest.scala b/src/test/scala/com/github/mdr/ascii/diagram/parser/Issue1DirectedEdgeNotParsedTest.scala
index 648fdd7..bd43d73 100644
--- a/src/test/scala/com/github/mdr/ascii/diagram/parser/Issue1DirectedEdgeNotParsedTest.scala
+++ b/src/test/scala/com/github/mdr/ascii/diagram/parser/Issue1DirectedEdgeNotParsedTest.scala
@@ -1,11 +1,10 @@
 package com.github.mdr.ascii.diagram.parser
 
-import org.scalatest.matchers.ShouldMatchers
-import org.scalatest.FlatSpec
+import org.scalatest.{FlatSpec, Matchers}
 import com.github.mdr.ascii.graph.Graph
 import com.github.mdr.ascii.diagram.Diagram
 
-class Issue1DirectedEdgeNotParsedTest extends FlatSpec with ShouldMatchers {
+class Issue1DirectedEdgeNotParsedTest extends FlatSpec with Matchers {
 
   "Parser" should "detect directed edge" in {
 
diff --git a/src/test/scala/com/github/mdr/ascii/graph/GraphGenerators.scala b/src/test/scala/com/github/mdr/ascii/graph/GraphGenerators.scala
index d2f3757..d320ca1 100644
--- a/src/test/scala/com/github/mdr/ascii/graph/GraphGenerators.scala
+++ b/src/test/scala/com/github/mdr/ascii/graph/GraphGenerators.scala
@@ -1,13 +1,15 @@
 package com.github.mdr.ascii.graph
 
 import org.scalacheck._
-import org.scalacheck.Gen.Params
+import org.scalacheck.Gen.Parameters
+
 import scala.util.Random
 import com.github.mdr.ascii.layout.cycles.CycleRemover
+import org.scalacheck.rng.Seed
 
 object GraphGenerators {
 
-  implicit val graphGen: Gen[Graph[String]] = Gen { p: Params ⇒ Some(RandomGraph.randomGraph(new Random(p.rng))) }
+  implicit val graphGen: Gen[Graph[String]] = Gen.choose(0, 9999999).map { seed ⇒ RandomGraph.randomGraph(new Random(scala.util.Random.nextLong)) }
 
   implicit val arbitraryGraph = Arbitrary(graphGen)
 
diff --git a/src/test/scala/com/github/mdr/ascii/graph/TopologicalSortSpecification.scala b/src/test/scala/com/github/mdr/ascii/graph/TopologicalSortSpecification.scala
index b28764e..eafa8e0 100644
--- a/src/test/scala/com/github/mdr/ascii/graph/TopologicalSortSpecification.scala
+++ b/src/test/scala/com/github/mdr/ascii/graph/TopologicalSortSpecification.scala
@@ -1,14 +1,9 @@
 package com.github.mdr.ascii.graph
 
-import org.scalacheck.Arbitrary
-import org.scalacheck.Gen
-import org.scalacheck.Gen.Params
-import org.scalacheck.Prop.forAll
-import org.scalacheck.Properties
-import org.scalacheck.Shrink
-import com.github.mdr.ascii.util.Utils
 import com.github.mdr.ascii.graph.GraphGenerators._
 import com.github.mdr.ascii.layout.cycles.CycleRemover
+import org.scalacheck.Prop.forAll
+import org.scalacheck.Properties
 
 object TopologicalSortSpecification extends Properties("Topological sort") {
 
diff --git a/src/test/scala/com/github/mdr/ascii/graph/TopologicalSortTest.scala b/src/test/scala/com/github/mdr/ascii/graph/TopologicalSortTest.scala
index ccdaa2e..433713f 100644
--- a/src/test/scala/com/github/mdr/ascii/graph/TopologicalSortTest.scala
+++ b/src/test/scala/com/github/mdr/ascii/graph/TopologicalSortTest.scala
@@ -1,10 +1,9 @@
 package com.github.mdr.ascii.graph
 
-import org.scalatest.FlatSpec
-import org.scalatest.matchers.ShouldMatchers
+import org.scalatest.{FlatSpec, Matchers}
 import org.scalatest.prop.Checkers
 
-class TopologicalSortTest extends FlatSpec with ShouldMatchers with Checkers {
+class TopologicalSortTest extends FlatSpec with Matchers with Checkers {
 
   check("""
          +-+   +-+ 
diff --git a/src/test/scala/com/github/mdr/ascii/gui/GUI.scala b/src/test/scala/com/github/mdr/ascii/gui/GUI.scala
index e9a3bf1..d2930e1 100644
--- a/src/test/scala/com/github/mdr/ascii/gui/GUI.scala
+++ b/src/test/scala/com/github/mdr/ascii/gui/GUI.scala
@@ -107,7 +107,8 @@ object Frame extends JFrame {
         vertical = verticalBox.isSelected,
         doubleVertices = doubleVerticesBox.isSelected,
         rounded = roundedBox.isSelected,
-        explicitAsciiBends = explicitAsciiBendsBox.isSelected)
+        explicitAsciiBends = explicitAsciiBendsBox.isSelected
+      )
 
   }
 
diff --git a/src/test/scala/com/github/mdr/ascii/layout/Issue3InfiniteLoopTest.scala b/src/test/scala/com/github/mdr/ascii/layout/Issue3InfiniteLoopTest.scala
index da17a30..65ce24a 100644
--- a/src/test/scala/com/github/mdr/ascii/layout/Issue3InfiniteLoopTest.scala
+++ b/src/test/scala/com/github/mdr/ascii/layout/Issue3InfiniteLoopTest.scala
@@ -1,15 +1,14 @@
 package com.github.mdr.ascii.layout
 
-import org.scalatest.matchers.ShouldMatchers
-import org.scalatest.FlatSpec
+import org.scalatest.{FlatSpec, Matchers}
 import com.github.mdr.ascii.graph.Graph
 
 // https://github.com/mdr/ascii-graphs/issues/3
-class Issue3InfiniteLoopTest extends FlatSpec with ShouldMatchers {
+class Issue3InfiniteLoopTest extends FlatSpec with Matchers {
 
   "Layouter" should "not go into an infinite loop" in {
     val v = Set("1", "2", "3", "7", "9")
-    val e = List("1" -> "3", "1" -> "7", "3" -> "2", "3" -> "9", "7" -> "9", "7" -> "2")
+    val e = List("1" → "3", "1" → "7", "3" → "2", "3" → "9", "7" → "9", "7" → "2")
     val graph = Graph(vertices = v, edges = e)
     GraphLayout.renderGraph(graph)
 
@@ -19,9 +18,9 @@ class Issue3InfiniteLoopTest extends FlatSpec with ShouldMatchers {
   "Layouter" should "really not go into an infinite loop this time" in {
 
     val v = Set("1", "2", "3", "4", "5", "6", "7", "8", "9", "10")
-    val e = List("1" -> "2", "1" -> "3", "1" -> "4", "1" -> "6", "1" -> "7", "1" -> "10",
-      "2" -> "3", "2" -> "4", "2" -> "5", "2" -> "6", "2" -> "7", "2" -> "8", "2" -> "10",
-      "3" -> "9", "4" -> "5", "4" -> "8", "7" -> "9")
+    val e = List("1" → "2", "1" → "3", "1" → "4", "1" → "6", "1" → "7", "1" → "10",
+      "2" → "3", "2" → "4", "2" → "5", "2" → "6", "2" → "7", "2" → "8", "2" → "10",
+      "3" → "9", "4" → "5", "4" → "8", "7" → "9")
 
     val graph = Graph(vertices = v, edges = e)
     GraphLayout.renderGraph(graph)
diff --git a/src/test/scala/com/github/mdr/ascii/layout/RoundTripTest.scala b/src/test/scala/com/github/mdr/ascii/layout/RoundTripTest.scala
index 784dbe1..59bde5f 100644
--- a/src/test/scala/com/github/mdr/ascii/layout/RoundTripTest.scala
+++ b/src/test/scala/com/github/mdr/ascii/layout/RoundTripTest.scala
@@ -1,11 +1,10 @@
 package com.github.mdr.ascii.layout
 
-import org.scalatest.FlatSpec
-import org.scalatest.matchers.ShouldMatchers
+import org.scalatest.{FlatSpec, Matchers}
 import com.github.mdr.ascii.graph.Graph
 import com.github.mdr.ascii.layout.RoundTripSpecification._
 
-class RoundTripTest extends FlatSpec with ShouldMatchers {
+class RoundTripTest extends FlatSpec with Matchers {
 
   "Round trip" should ("not overwrite an arrow") in {
     checkRoundTrip(Graph.fromDiagram("""
diff --git a/src/test/scala/com/github/mdr/ascii/layout/cycles/CycleRemoverSpecification.scala b/src/test/scala/com/github/mdr/ascii/layout/cycles/CycleRemoverSpecification.scala
index 7b356c6..0543eff 100644
--- a/src/test/scala/com/github/mdr/ascii/layout/cycles/CycleRemoverSpecification.scala
+++ b/src/test/scala/com/github/mdr/ascii/layout/cycles/CycleRemoverSpecification.scala
@@ -1,18 +1,10 @@
 package com.github.mdr.ascii.layout.cycles
 
-import scala.util.Random._
-
-import org.scalacheck.Arbitrary
-import org.scalacheck.Gen
-import org.scalacheck.Gen.Params
+import com.github.mdr.ascii.graph.{Graph, GraphUtils}
+import com.github.mdr.ascii.graph.GraphGenerators._
+import com.github.mdr.ascii.util.Utils
 import org.scalacheck.Prop.forAll
 import org.scalacheck.Properties
-import org.scalacheck.Shrink
-
-import com.github.mdr.ascii.graph.Graph
-import com.github.mdr.ascii.graph.GraphUtils
-import com.github.mdr.ascii.util.Utils
-import com.github.mdr.ascii.graph.GraphGenerators._
 
 object CycleRemoverSpecification extends Properties("CycleRemover") {
 
diff --git a/src/test/scala/com/github/mdr/ascii/layout/cycles/CycleRemoverTest.scala b/src/test/scala/com/github/mdr/ascii/layout/cycles/CycleRemoverTest.scala
index 201c4b1..60276e7 100644
--- a/src/test/scala/com/github/mdr/ascii/layout/cycles/CycleRemoverTest.scala
+++ b/src/test/scala/com/github/mdr/ascii/layout/cycles/CycleRemoverTest.scala
@@ -1,13 +1,11 @@
 package com.github.mdr.ascii.layout.cycles
 
-import org.scalatest.FlatSpec
-import org.scalatest.matchers.ShouldMatchers
-
+import org.scalatest.{FlatSpec, Matchers}
 import com.github.mdr.ascii.graph.Graph
 import com.github.mdr.ascii.graph.GraphUtils
 import com.github.mdr.ascii.util.Utils
 
-class CycleRemoverTest extends FlatSpec with ShouldMatchers {
+class CycleRemoverTest extends FlatSpec with Matchers {
 
   check("""
          +-+   +-+ 
diff --git a/src/test/scala/com/github/mdr/ascii/layout/cycles/GraphReflowTest.scala b/src/test/scala/com/github/mdr/ascii/layout/cycles/GraphReflowTest.scala
index eba1d34..732a9e5 100644
--- a/src/test/scala/com/github/mdr/ascii/layout/cycles/GraphReflowTest.scala
+++ b/src/test/scala/com/github/mdr/ascii/layout/cycles/GraphReflowTest.scala
@@ -1,12 +1,10 @@
 package com.github.mdr.ascii.layout.cycles
 
-import org.scalatest.FlatSpec
-import org.scalatest.matchers.ShouldMatchers
-
+import org.scalatest.{FlatSpec, Matchers}
 import com.github.mdr.ascii.graph.Graph
 import com.github.mdr.ascii.util.Utils
 
-class GraphReflowTest extends FlatSpec with ShouldMatchers {
+class GraphReflowTest extends FlatSpec with Matchers {
 
   reflowingGraph("""
          +-+   +-+ 
@@ -28,7 +26,7 @@ class GraphReflowTest extends FlatSpec with ShouldMatchers {
          +-+   +-+ 
          |A|-->|B| 
          +-+   +-+ """).
-    havingReversedEdges("A" -> "B")
+    havingReversedEdges("A" → "B")
 
   reflowingGraph("""
          +-+   +-+   +-+ 
@@ -45,7 +43,7 @@ class GraphReflowTest extends FlatSpec with ShouldMatchers {
           ^           |  
           |           |  
           -------------  """).
-    havingReversedEdges("B" -> "A", "C" -> "B")
+    havingReversedEdges("B" → "A", "C" → "B")
 
   reflowingGraph("""
          +-+   +-+ 
@@ -62,7 +60,7 @@ class GraphReflowTest extends FlatSpec with ShouldMatchers {
           |     ^  
           |     |  
           -------  """).
-    havingReversedEdges("A" -> "C")
+    havingReversedEdges("A" → "C")
 
   reflowingGraph("""
           +-+   +-+     
@@ -81,7 +79,7 @@ class GraphReflowTest extends FlatSpec with ShouldMatchers {
        |   |     |   |  
        |   -------   |  
        ---------------  """).
-    havingReversedEdges("A" -> "C", "A" -> "C")
+    havingReversedEdges("A" → "C", "A" → "C")
 
   reflowingGraph("""
                +-+ 
diff --git a/src/test/scala/com/github/mdr/ascii/layout/layering/AssignLayersSpecification.scala b/src/test/scala/com/github/mdr/ascii/layout/layering/AssignLayersSpecification.scala
index b958939..093d845 100644
--- a/src/test/scala/com/github/mdr/ascii/layout/layering/AssignLayersSpecification.scala
+++ b/src/test/scala/com/github/mdr/ascii/layout/layering/AssignLayersSpecification.scala
@@ -1,11 +1,7 @@
 package com.github.mdr.ascii.layout.layering
 
-import org.scalacheck.Arbitrary
-import org.scalacheck.Gen
-import org.scalacheck.Gen.Params
 import org.scalacheck.Prop.forAll
 import org.scalacheck.Properties
-import org.scalacheck.Shrink
 import com.github.mdr.ascii.graph.Graph
 import com.github.mdr.ascii.graph.GraphGenerators._
 import com.github.mdr.ascii.layout.cycles.CycleRemover
@@ -19,7 +15,7 @@ object AssignLayersSpecification extends Properties("Assign Layers") {
       (for {
         (layer, index) ← layering.layers.zipWithIndex
         v ← layer.vertices
-      } yield v -> index).toMap
+      } yield v → index).toMap
     cycleRemovalResult.dag.edges.forall {
       case (from, to) ⇒
         getLayerIndex(realVertices(from)) < getLayerIndex(realVertices(to))
diff --git a/src/test/scala/com/github/mdr/ascii/layout/layering/CrossingCalculatorTest.scala b/src/test/scala/com/github/mdr/ascii/layout/layering/CrossingCalculatorTest.scala
index 6385167..0c9b235 100644
--- a/src/test/scala/com/github/mdr/ascii/layout/layering/CrossingCalculatorTest.scala
+++ b/src/test/scala/com/github/mdr/ascii/layout/layering/CrossingCalculatorTest.scala
@@ -1,14 +1,12 @@
 package com.github.mdr.ascii.layout.layering
 
-import org.scalatest.FlatSpec
-import org.scalatest.matchers.ShouldMatchers
-
+import org.scalatest.{FlatSpec, Matchers}
 import com.github.mdr.ascii.graph.GraphUtils
 import com.github.mdr.ascii.graph.Graph
 import com.github.mdr.ascii.util.Utils
 import com.github.mdr.ascii.layout.cycles.CycleRemover
 
-class CrossingCalculatorTest extends FlatSpec with ShouldMatchers {
+class CrossingCalculatorTest extends FlatSpec with Matchers {
 
   // Note: layer ordering in test data is done alphabetically
 
diff --git a/src/test/scala/com/github/mdr/ascii/layout/layering/LongestDistanceToSinkSpecification.scala b/src/test/scala/com/github/mdr/ascii/layout/layering/LongestDistanceToSinkSpecification.scala
index 5e17a35..87151cb 100644
--- a/src/test/scala/com/github/mdr/ascii/layout/layering/LongestDistanceToSinkSpecification.scala
+++ b/src/test/scala/com/github/mdr/ascii/layout/layering/LongestDistanceToSinkSpecification.scala
@@ -1,15 +1,10 @@
 package com.github.mdr.ascii.layout.layering
 
-import org.scalacheck.Arbitrary
-import org.scalacheck.Gen
-import org.scalacheck.Gen.Params
 import org.scalacheck.Prop.forAll
 import org.scalacheck.Properties
-import org.scalacheck.Shrink
 
 import com.github.mdr.ascii.graph.Graph
 import com.github.mdr.ascii.graph.GraphGenerators._
-import com.github.mdr.ascii.layout.cycles.CycleRemover
 
 object LongestDistanceToSinkSpecification extends Properties("LongestDistanceToSink") {
 
diff --git a/src/test/scala/com/github/mdr/ascii/layout/layering/LongestDistanceToSinkTest.scala b/src/test/scala/com/github/mdr/ascii/layout/layering/LongestDistanceToSinkTest.scala
index 0843f01..30c47ef 100644
--- a/src/test/scala/com/github/mdr/ascii/layout/layering/LongestDistanceToSinkTest.scala
+++ b/src/test/scala/com/github/mdr/ascii/layout/layering/LongestDistanceToSinkTest.scala
@@ -1,18 +1,15 @@
 package com.github.mdr.ascii.layout.layering
 
-import org.scalatest.FlatSpec
-import org.scalatest.matchers.ShouldMatchers
+import org.scalatest.{FlatSpec, Matchers}
 import com.github.mdr.ascii.graph.Graph
-import com.github.mdr.ascii.graph.GraphUtils
-import com.github.mdr.ascii.util.Utils
 
-class LongestDistanceToSinkTest extends FlatSpec with ShouldMatchers {
+class LongestDistanceToSinkTest extends FlatSpec with Matchers {
 
   distancesToSinks("""
          +-+   +-+   +-+ 
          |A|-->|B|-->|C| 
          +-+   +-+   +-+ """) shouldBe
-    ("A" -> 2, "B" -> 1, "C" -> 0)
+    ("A" → 2, "B" → 1, "C" → 0)
 
   distancesToSinks("""
          +-+   +-+   +-+ 
@@ -21,7 +18,7 @@ class LongestDistanceToSinkTest extends FlatSpec with ShouldMatchers {
           |           ^  
           |           |  
           -------------  """) shouldBe
-    ("A" -> 1, "B" -> 1, "C" -> 0)
+    ("A" → 1, "B" → 1, "C" → 0)
 
   distancesToSinks("""
          +-+   +-+   +-+ 
@@ -30,14 +27,14 @@ class LongestDistanceToSinkTest extends FlatSpec with ShouldMatchers {
           |           ^  
           |           |  
           -------------  """) shouldBe
-    ("A" -> 2, "B" -> 1, "C" -> 0)
+    ("A" → 2, "B" → 1, "C" → 0)
 
   distancesToSinks("""
           +-+ 
           |B| 
           +-+ 
            """) shouldBe
-    ("B" -> 0)
+    ("B" → 0)
 
   distancesToSinks("") shouldBe ()
 
diff --git a/src/test/scala/com/github/mdr/ascii/util/QuadTreeTest.scala b/src/test/scala/com/github/mdr/ascii/util/QuadTreeTest.scala
index 6a0c6d6..eb9f510 100644
--- a/src/test/scala/com/github/mdr/ascii/util/QuadTreeTest.scala
+++ b/src/test/scala/com/github/mdr/ascii/util/QuadTreeTest.scala
@@ -1,10 +1,9 @@
 package com.github.mdr.ascii.util
 
-import org.scalatest.FlatSpec
-import org.scalatest.matchers.ShouldMatchers
+import org.scalatest.{FlatSpec, Matchers}
 import com.github.mdr.ascii.common._
 
-class QuadTreeTest extends FlatSpec with ShouldMatchers {
+class QuadTreeTest extends FlatSpec with Matchers {
 
   "A QuadTree" should "work with one element" in {
     val tree = new QuadTree[Region](Dimension(16, 16))