toAllocate := []int{
		10000,
		10030,
		10030,
		10040,
	}
	expectedErrors := []error{
		ErrAllocated,
		nil,
		ErrAllocated,
		nil,
	}
	op := StartOperation(r, true)
	for i, port := range toAllocate {
		err := op.Allocate(port)
		if err != expectedErrors[i] {
			t.Errorf("%v: expected error %v but got %v", i, expectedErrors[i], err)
		}
	}

	shouldRollback  bool
	dryRun          bool
}

// Creates a portAllocationOperation, tracking a set of allocations & releases
// If dryRun is specified, never actually allocate or release anything
func StartOperation(pa Interface, dryRun bool) *PortAllocationOperation {
	op := &PortAllocationOperation{}
	op.pa = pa
	op.allocated = []int{}
	op.releaseDeferred = []int{}
	op.shouldRollback = true
	op.dryRun = dryRun
	return op