gistfile1.kt

package samples

import kspec.framework.*

spec public fun calculatorSpecs() {

    given("a calculator", {

        val calculator = Calculator()

        on("calling sum with two numbers", {

            val sum = calculator.sum(2, 4)

            it("should return the result of adding the first number to the second", {

                shouldEqual(6, sum)

            })


        })

    })
}

your example might look like this:

describe("calculator", {
  val calculator = Calculator()
  describe("adding two numbers", {
    val sum = calculator.sum(2, 4)
    it("should return the result of adding the first number to the second", {
      shouldEqual(6, sum)
    })
  })
})