pr, err := net.ParsePortRange("10000-10200")
	if err != nil {
		t.Fatal(err)
	}

	// Allocate some ports before calling
	previouslyAllocated := []int{10000, 10010, 10020}
	r, err := NewInMemory(*pr)
	if err != nil {
		t.Fatal(err)
	}
	for _, port := range previouslyAllocated {
		_ = r.Allocate(port)
	}
	freeAtStart := r.Free()

	// Do some allocations with a dry run operation

	}

	var err error
	a.alloc, err = allocatorFactory(max, rangeSpec, calculateRangeOffset(pr))
	if err != nil {
		return nil, err
	}

	return a, err
}

// NewInMemory creates an in-memory allocator.
func NewInMemory(pr net.PortRange) (*PortAllocator, error) {
	return New(pr, func(max int, rangeSpec string, offset int) (allocator.Interface, error) {