Wiremock: Error al intentar usar wiremock en sbt.

Hola,
Estoy intentando usar wiremock en una aplicación Scala / Play. Pero obteniendo el siguiente error.

Mis dependencias en build.sbt se ven así:

libraryDependencies ++= Seq(
  "com.github.tomakehurst" % "wiremock" % "2.6.0" % IntegrationTest,
  "org.mockito" % "mockito-core" % "1.9.0" % "test",
  "org.jsoup" % "jsoup" % "1.10.2" % "test",
  "org.scalactic" %% "scalactic" % "3.0.1" % "test, it",
  "org.scalatest" %% "scalatest" % "3.0.1" % "test, it",
  "org.scalatestplus.play" %% "scalatestplus-play" % "3.0.0-RC1" % IntegrationTest,
  guice
)

Por favor, avíseme si me falta algo ...

java.lang.NoClassDefFoundError: org/eclipse/jetty/http/HttpGenerator$CachedHttpField
        at com.github.tomakehurst.wiremock.jetty9.JettyHttpServer.createServer(JettyHttpServer.java:117)
        at com.github.tomakehurst.wiremock.jetty9.JettyHttpServer.<init>(JettyHttpServer.java:68)
        at com.github.tomakehurst.wiremock.jetty9.JettyHttpServerFactory.buildHttpServer(JettyHttpServerFactory.java:31)
        at com.github.tomakehurst.wiremock.WireMockServer.<init>(WireMockServer.java:73)
        at helpers.WiremockHelper.wireMockServer(WiremockHelper.scala:59)
        at helpers.WiremockHelper.wireMockServer$(WiremockHelper.scala:59)
        at controllers.ApplicationControllerITSpec.wireMockServer$lzycompute(ApplicationControllerITSpec.scala:10)
        at controllers.ApplicationControllerITSpec.wireMockServer(ApplicationControllerITSpec.scala:10)
        at helpers.WiremockHelper.startWiremock(WiremockHelper.scala:62)
        at helpers.WiremockHelper.startWiremock$(WiremockHelper.scala:61)
        at controllers.ApplicationControllerITSpec.startWiremock(ApplicationControllerITSpec.scala:10)
        at helpers.IntegrationSpecBase.beforeAll(IntegrationSpecBase.scala:35)
        at helpers.IntegrationSpecBase.beforeAll$(IntegrationSpecBase.scala:33)
        at controllers.ApplicationControllerITSpec.beforeAll(ApplicationControllerITSpec.scala:10)
        at org.scalatest.BeforeAndAfterAll.liftedTree1$1(BeforeAndAfterAll.scala:212)
        at org.scalatest.BeforeAndAfterAll.run(BeforeAndAfterAll.scala:210)
        at org.scalatest.BeforeAndAfterAll.run$(BeforeAndAfterAll.scala:208)
        at controllers.ApplicationControllerITSpec.run(ApplicationControllerITSpec.scala:10)
        at org.scalatest.tools.Framework.org$scalatest$tools$Framework$$runSuite(Framework.scala:314)
        at org.scalatest.tools.Framework$ScalaTestTask.execute(Framework.scala:507)
        at sbt.TestRunner.runTest$1(TestFramework.scala:76)
        at sbt.TestRunner.run(TestFramework.scala:85)
        at sbt.TestFramework$$anon$2$$anonfun$$init$$1$$anonfun$apply$8.apply(TestFramework.scala:202)
        at sbt.TestFramework$$anon$2$$anonfun$$init$$1$$anonfun$apply$8.apply(TestFramework.scala:202)
        at sbt.TestFramework$.sbt$TestFramework$$withContextLoader(TestFramework.scala:185)
        at sbt.TestFramework$$anon$2$$anonfun$$init$$1.apply(TestFramework.scala:202)
        at sbt.TestFramework$$anon$2$$anonfun$$init$$1.apply(TestFramework.scala:202)
        at sbt.TestFunction.apply(TestFramework.scala:207)
        at sbt.Tests$$anonfun$9.apply(Tests.scala:216)
        at sbt.Tests$$anonfun$9.apply(Tests.scala:216)
        at sbt.std.Transform$$anon$3$$anonfun$apply$2.apply(System.scala:44)
        at sbt.std.Transform$$anon$3$$anonfun$apply$2.apply(System.scala:44)
        at sbt.std.Transform$$anon$4.work(System.scala:63)
        at sbt.Execute$$anonfun$submit$1$$anonfun$apply$1.apply(Execute.scala:228)
        at sbt.Execute$$anonfun$submit$1$$anonfun$apply$1.apply(Execute.scala:228)
        at sbt.ErrorHandling$.wideConvert(ErrorHandling.scala:17)
        at sbt.Execute.work(Execute.scala:237)
        at sbt.Execute$$anonfun$submit$1.apply(Execute.scala:228)
        at sbt.Execute$$anonfun$submit$1.apply(Execute.scala:228)
        at sbt.ConcurrentRestrictions$$anon$4$$anonfun$1.apply(ConcurrentRestrictions.scala:159)
        at sbt.CompletionService$$anon$2.call(CompletionService.scala:28)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.ClassNotFoundException: org.eclipse.jetty.http.HttpGenerator$CachedHttpField
        at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
        at com.github.tomakehurst.wiremock.jetty9.JettyHttpServer.createServer(JettyHttpServer.java:117)
        at com.github.tomakehurst.wiremock.jetty9.JettyHttpServer.<init>(JettyHttpServer.java:68)
        at com.github.tomakehurst.wiremock.jetty9.JettyHttpServerFactory.buildHttpServer(JettyHttpServerFactory.java:31)
        at com.github.tomakehurst.wiremock.WireMockServer.<init>(WireMockServer.java:73)
        at helpers.WiremockHelper.wireMockServer(WiremockHelper.scala:59)
        at helpers.WiremockHelper.wireMockServer$(WiremockHelper.scala:59)
        at controllers.ApplicationControllerITSpec.wireMockServer$lzycompute(ApplicationControllerITSpec.scala:10)
        at controllers.ApplicationControllerITSpec.wireMockServer(ApplicationControllerITSpec.scala:10)
        at helpers.WiremockHelper.startWiremock(WiremockHelper.scala:62)
        at helpers.WiremockHelper.startWiremock$(WiremockHelper.scala:61)
        at controllers.ApplicationControllerITSpec.startWiremock(ApplicationControllerITSpec.scala:10)
        at helpers.IntegrationSpecBase.beforeAll(IntegrationSpecBase.scala:35)
        at helpers.IntegrationSpecBase.beforeAll$(IntegrationSpecBase.scala:33)
        at controllers.ApplicationControllerITSpec.beforeAll(ApplicationControllerITSpec.scala:10)
        at org.scalatest.BeforeAndAfterAll.liftedTree1$1(BeforeAndAfterAll.scala:212)
        at org.scalatest.BeforeAndAfterAll.run(BeforeAndAfterAll.scala:210)
        at org.scalatest.BeforeAndAfterAll.run$(BeforeAndAfterAll.scala:208)
        at controllers.ApplicationControllerITSpec.run(ApplicationControllerITSpec.scala:10)
        at org.scalatest.tools.Framework.org$scalatest$tools$Framework$$runSuite(Framework.scala:314)
        at org.scalatest.tools.Framework$ScalaTestTask.execute(Framework.scala:507)
        at sbt.TestRunner.runTest$1(TestFramework.scala:76)
        at sbt.TestRunner.run(TestFramework.scala:85)
        at sbt.TestFramework$$anon$2$$anonfun$$init$$1$$anonfun$apply$8.apply(TestFramework.scala:202)
        at sbt.TestFramework$$anon$2$$anonfun$$init$$1$$anonfun$apply$8.apply(TestFramework.scala:202)
        at sbt.TestFramework$.sbt$TestFramework$$withContextLoader(TestFramework.scala:185)
        at sbt.TestFramework$$anon$2$$anonfun$$init$$1.apply(TestFramework.scala:202)
        at sbt.TestFramework$$anon$2$$anonfun$$init$$1.apply(TestFramework.scala:202)
        at sbt.TestFunction.apply(TestFramework.scala:207)
        at sbt.Tests$$anonfun$9.apply(Tests.scala:216)
        at sbt.Tests$$anonfun$9.apply(Tests.scala:216)
        at sbt.std.Transform$$anon$3$$anonfun$apply$2.apply(System.scala:44)
        at sbt.std.Transform$$anon$3$$anonfun$apply$2.apply(System.scala:44)
        at sbt.std.Transform$$anon$4.work(System.scala:63)
        at sbt.Execute$$anonfun$submit$1$$anonfun$apply$1.apply(Execute.scala:228)
        at sbt.Execute$$anonfun$submit$1$$anonfun$apply$1.apply(Execute.scala:228)
        at sbt.ErrorHandling$.wideConvert(ErrorHandling.scala:17)
        at sbt.Execute.work(Execute.scala:237)
        at sbt.Execute$$anonfun$submit$1.apply(Execute.scala:228)
        at sbt.Execute$$anonfun$submit$1.apply(Execute.scala:228)
        at sbt.ConcurrentRestrictions$$anon$4$$anonfun$1.apply(ConcurrentRestrictions.scala:159)
        at sbt.CompletionService$$anon$2.call(CompletionService.scala:28)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at java.lang.Thread.run(Thread.java:745)