package main

import "testing"

// A reset re-bases from a fresh capture while the ring still holds buckets from
// just before it, so the newest bucket must not be left behind the new origin.
func TestResetDoesNotUnderflowTotals(t *testing.T) {
	d := &direction{
		win:     newRateWindow(8),
		cable:   newCableStats(),
		rxStats: []*rxStats{{}},
	}

	d.rxStats[0].frames.Store(100)
	d.rxStats[0].bytes.Store(6400)
	d.sample()

	d.rxStats[0].frames.Store(150)
	d.rxStats[0].bytes.Store(9600)
	d.reset()

	v := d.displayView()
	if v.rxFrames != 0 {
		t.Errorf("rxFrames = %d, want 0", v.rxFrames)
	}
	if v.rxBytes != 0 {
		t.Errorf("rxBytes = %d, want 0", v.rxBytes)
	}

	// The rolling window and the rates are about now rather than since the
	// reset, so the buckets from before it have to survive.
	if got := d.win.count(); got < 2 {
		t.Errorf("ring holds %d buckets after reset, want the pre-reset history kept", got)
	}
}