Just trying Spek for the first time, getting this ...

# spek

[Ian]

Just trying Spek for the first time, getting this exception:

Jul 05, 2017 9:50:39 PM org.junit.platform.launcher.core.ServiceLoaderTestEngineRegistry loadTestEngines
INFO: Discovered TestEngines with IDs: [spek]
Exception in thread "main" java.lang.AbstractMethodError: Method org/jetbrains/spek/engine/Scope$Group.isTest()Z is abstract
	at org.jetbrains.spek.engine.Scope$Group.isTest(Scope.kt)
	at org.junit.platform.engine.TestDescriptor.hasTests(TestDescriptor.java:160)
	at org.junit.platform.launcher.core.Root.lambda$static$0(Root.java:33)
	at org.junit.platform.launcher.core.Root$$Lambda$18/1562557367.visit(Unknown Source)
	at org.junit.platform.engine.TestDescriptor.accept(TestDescriptor.java:179)
	at org.junit.platform.engine.TestDescriptor.lambda$accept$0(TestDescriptor.java:181)
	at org.junit.platform.engine.TestDescriptor$$Lambda$32/534906248.accept(Unknown Source)
	at java.lang.Iterable.forEach(Iterable.java:75)
	at org.junit.platform.engine.TestDescriptor.accept(TestDescriptor.java:181)
	at org.junit.platform.launcher.core.Root.lambda$acceptInAllTestEngines$2(Root.java:85)
	at org.junit.platform.launcher.core.Root$$Lambda$31/1997963191.accept(Unknown Source)
	at java.util.LinkedHashMap$LinkedValues.forEach(LinkedHashMap.java:600)
	at org.junit.platform.launcher.core.Root.acceptInAllTestEngines(Root.java:85)
	at org.junit.platform.launcher.core.Root.prune(Root.java:77)
	at org.junit.platform.launcher.core.DefaultLauncher.discoverRoot(DefaultLauncher.java:117)
	at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:85)
	at org.jetbrains.spek.tooling.runner.junit.JUnitPlatformSpekRunner.run(JUnitPlatformSpekRunner.kt:107)
	at org.jetbrains.spek.tooling.MainKt.main(Main.kt:58)