afterTestRuns = (initiator, test, samples, idx) => {
      const testName = test.name

      if (agent) {
        helper.unloadAgent(agent)
      }

      if (typeof test.teardown === 'function') {
        test.teardown()
      }

      suite.samples[testName] = samples
      return testIterator(initiator, idx + 1)
    }
@param {function} initiator The test runner `startTest`
@param {object} test configuration for the test
@param {Array} samples Array of the CPU deltas from this test
@param {number} idx Index of the current test run
@returns {function} The next instance in the recursive chain of initiators (`startTest`)
  and returned functions (`afterTestRuns`)