Support object instance tests

[mfulton26]

IntelliJ IDEA offers to run object speks annotated with @RunWith(JUnitPlatform::class) but running such results in a KotlinNullPointerException. I personally like using object for tests/specifications as they are indeed singletons (unless data driven, but that usually happens within a test/specification and not at the top-level and if it does then enum/class can be used with whatever annotations/etc. the framework supports for driving such).

@RunWith(JUnitPlatform::class)
object ExampleSpek : Spek({
    group("a") {
        test("1") {}
        test("2") {}
    }
    group("b") {
        group("1") {
            test("A") {}
        }
        group("2") {
            test("A") {}
            test("B") {}
        }
    }
})

Aug 26, 2016 10:49:17 AM org.junit.platform.launcher.core.ServiceLoaderTestEngineRegistry loadTestEngines
INFO: Discovered TestEngines with IDs: [spek]

kotlin.KotlinNullPointerException
    at org.jetbrains.spek.engine.SpekTestEngine.resolveSpec(SpekTestEngine.kt:97)
    at org.jetbrains.spek.engine.SpekTestEngine.resolveSpecs(SpekTestEngine.kt:62)
    at org.jetbrains.spek.engine.SpekTestEngine.discover(SpekTestEngine.kt:36)
    at org.junit.platform.launcher.core.DefaultLauncher.discoverRoot(DefaultLauncher.java:108)
    at org.junit.platform.launcher.core.DefaultLauncher.discover(DefaultLauncher.java:78)
    at org.junit.platform.runner.JUnitPlatform.generateTestTree(JUnitPlatform.java:113)
    at org.junit.platform.runner.JUnitPlatform.<init>(JUnitPlatform.java:96)
    at org.junit.platform.runner.JUnitPlatform.<init>(JUnitPlatform.java:88)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
    at org.junit.internal.builders.AnnotatedBuilder.buildRunner(AnnotatedBuilder.java:104)
    at org.junit.internal.builders.AnnotatedBuilder.runnerForClass(AnnotatedBuilder.java:86)
    at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
    at org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:26)
    at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
    at org.junit.internal.requests.ClassRequest.getRunner(ClassRequest.java:33)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:96)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:42)
    at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:262)
    at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:84)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)

[raniejade]

Good point, thanks! We will look into it after the 1.0 release.

[raniejade]

Resolved by b9967f3.