test: Use kotest

src/main/kotlin/util/JvmUtil.kt

@@ -0,0 +1,32 @@
+package moe.nea.firmament.util
+
+import com.sun.tools.attach.VirtualMachine
+import java.lang.management.ManagementFactory
+import java.nio.file.Path
+import kotlin.io.path.absolutePathString
+
+object JvmUtil {
+	fun guessJVMPid(): String {
+		val name = ManagementFactory.getRuntimeMXBean().name
+		val pid = name.substringBefore('@')
+		ErrorUtil.softCheck("Not a valid PID: $pid", pid.toIntOrNull() != null)
+		return pid
+	}
+
+	fun getVM(): VirtualMachine {
+		return VirtualMachine.attach(guessJVMPid())
+	}
+
+	fun useVM(block: (VirtualMachine) -> Unit) {
+		val vm = getVM()
+		block(vm)
+		vm.detach()
+	}
+
+	fun loadAgent(jarPath: Path, options: String? = null) {
+		useVM {
+			it.loadAgent(jarPath.absolutePathString(), options)
+		}
+	}
+
+}

src/main/kotlin/util/MC.kt

@@ -105,7 +105,7 @@ object MC {
 	inline val currentRegistries: RegistryWrapper.WrapperLookup? get() = world?.registryManager
 	val defaultRegistries: RegistryWrapper.WrapperLookup by lazy { BuiltinRegistries.createWrapperLookup() }
 	inline val currentOrDefaultRegistries get() = currentRegistries ?: defaultRegistries
-	val defaultItems: RegistryWrapper.Impl<Item> = defaultRegistries.getOrThrow(RegistryKeys.ITEM)
+	val defaultItems: RegistryWrapper.Impl<Item> by lazy { defaultRegistries.getOrThrow(RegistryKeys.ITEM) }
 	var lastWorld: World? = null
 		get() {
 			field = world ?: field

src/main/kotlin/util/TestUtil.kt

@@ -1,5 +1,8 @@
 package moe.nea.firmament.util
 
 object TestUtil {
-	val isInTest = Thread.currentThread().stackTrace.any { it.className.startsWith("org.junit.") }
+	val isInTest =
+		Thread.currentThread().stackTrace.any {
+			it.className.startsWith("org.junit.") || it.className.startsWith("io.kotest.")
+		}
 }