Kotest: Getting a fresh context per test with and without IsolationMode.InstancePerTest

MyTestSuiteInstancePerTest.kt

import io.kotest.core.spec.IsolationMode
import io.kotest.core.spec.style.FunSpec
import io.kotest.matchers.shouldBe

class MyTestSuiteInstancePerTest : FunSpec() {

    override fun isolationMode(): IsolationMode = IsolationMode.InstancePerTest

    private class MyClass(var myProperty: Int = 1)

    private val myObject = MyClass()

    init {
        test("one") {
            myObject.myProperty shouldBe 1
            myObject.myProperty += 10
            myObject.myProperty shouldBe 11
        }

        test("two") {
            myObject.myProperty shouldBe 1
            myObject.myProperty += 20
            myObject.myProperty shouldBe 21
        }
    }
}

MyTestSuiteWithoutIsolation1.kt

import io.kotest.core.spec.style.FunSpec
import io.kotest.matchers.shouldBe

class MyTestSuiteWithoutIsolation1 : FunSpec() {

    private class MyClass(var myProperty: Int = 1)

    private class MyContext(val myObject: MyClass = MyClass())

    private fun myTest(name: String, action: suspend MyContext.() -> Unit) = test(name) {
        MyContext().action()
    }

    init {
        myTest("one") {
            myObject.myProperty shouldBe 1
            myObject.myProperty += 10
            myObject.myProperty shouldBe 11
        }

        myTest("two") {
            myObject.myProperty shouldBe 1
            myObject.myProperty += 20
            myObject.myProperty shouldBe 21
        }
    }
}

MyTestSuiteWithoutIsolation2.kt

import io.kotest.core.spec.style.FunSpec
import io.kotest.matchers.shouldBe

class MyTestSuiteWithoutIsolation2 : FunSpec() {

    private class MyClass(var myProperty: Int = 1)

    private class MyContext {
        val myObject: MyClass = MyClass()
    }

    init {
        test("one", MyContext()) {
            myObject.myProperty shouldBe 1
            myObject.myProperty += 10
            myObject.myProperty shouldBe 11
        }

        test("two", MyContext()) {
            myObject.myProperty shouldBe 1
            myObject.myProperty += 20
            myObject.myProperty shouldBe 21
        }
    }
}

fun <Context> FunSpec.test(name: String, context: Context, action: suspend Context.() -> Unit) = test(name) {
    context.action()
}