path: root/les/randselect_test.go

// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package les

import (
    "math/rand"
    "testing"
)

type testWrsItem struct {
    idx  int
    widx *int
}

func (t *testWrsItem) Weight() int64 {
    w := *t.widx
    if w == -1 || w == t.idx {
        return int64(t.idx + 1)
    }
    return 0
}

func TestWeightedRandomSelect(t *testing.T) {
    testFn := func(cnt int) {
        s := newWeightedRandomSelect()
        w := -1
        list := make([]testWrsItem, cnt)
        for i := range list {
            list[i] = testWrsItem{idx: i, widx: &w}
            s.update(&list[i])
        }
        w = rand.Intn(cnt)
        c := s.choose()
        if c == nil {
            t.Errorf("expected item, got nil")
        } else {
            if c.(*testWrsItem).idx != w {
                t.Errorf("expected another item")
            }
        }
        w = -2
        if s.choose() != nil {
            t.Errorf("expected nil, got item")
        }
    }
    testFn(1)
    testFn(10)
    testFn(100)
    testFn(1000)
    testFn(10000)
    testFn(100000)
    testFn(1000000)
}