plugeth/swarm/storage/mru/lookup/lookup_test.go
Javier Peletier 2c110c81ee Swarm MRUs: Adaptive frequency / Predictable lookups / API simplification (#17559)
* swarm/storage/mru: Adaptive Frequency

swarm/storage/mru/lookup: fixed getBaseTime
Added NewEpoch constructor

swarm/api/client: better error handling in GetResource()


swarm/storage/mru: Renamed structures.
Renamed ResourceMetadata to ResourceID. 
Renamed ResourceID.Name to ResourceID.Topic

swarm/storage/mru: Added binarySerializer interface and test tools

swarm/storage/mru/lookup: Changed base time to time and + marshallers

swarm/storage/mru:  Added ResourceID (former resourceMetadata)

swarm/storage/mru: Added ResourceViewId and serialization tests

swarm/storage/mru/lookup: fixed epoch unmarshaller. Added Epoch Equals

swarm/storage/mru: Fixes as per review comments

cmd/swarm: reworded resource create/update help text regarding topic

swarm/storage/mru: Added UpdateLookup and serializer tests

swarm/storage/mru: Added UpdateHeader, serializers and tests

swarm/storage/mru: changed UpdateAddr / epoch to Base()

swarm/storage/mru: Added resourceUpdate serializer and tests

swarm/storage/mru: Added SignedResourceUpdate tests and serializers

swarm/storage/mru/lookup: fixed GetFirstEpoch bug

swarm/storage/mru: refactor, comments, cleanup

Also added tests for Topic
swarm/storage/mru: handler tests pass

swarm/storage/mru: all resource package tests pass

swarm/storage/mru: resource test pass after adding
timestamp checking support

swarm/storage/mru: Added JSON serializers to ResourceIDView structures

swarm/storage/mru: Sever, client, API test pass

swarm/storage/mru: server test pass

swarm/storage/mru: Added topic length check

swarm/storage/mru: removed some literals,
improved "previous lookup" test case

swarm/storage/mru: some fixes and comments as per review

swarm/storage/mru: first working version without metadata chunk

swarm/storage/mru: Various fixes as per review

swarm/storage/mru: client test pass

swarm/storage/mru: resource query strings and manifest-less queries


swarm/storage/mru: simplify naming

swarm/storage/mru: first autofreq working version



swarm/storage/mru: renamed ToValues to AppendValues

swarm/resource/mru: Added ToValues / FromValues for URL query strings

swarm/storage/mru: Changed POST resource to work with query strings.
No more JSON.

swarm/storage/mru: removed resourceid

swarm/storage/mru: Opened up structures

swarm/storage/mru: Merged Request and SignedResourceUpdate

swarm/storage/mru: removed initial data from CLI resource create

swarm/storage/mru: Refactor Topic as a direct fixed-length array

swarm/storage/mru/lookup: Comprehensive GetNextLevel tests

swarm/storage/mru: Added comments

Added length checks in Topic
swarm/storage/mru: fixes in tests and some code comments

swarm/storage/mru/lookup: new optimized lookup algorithm

swarm/api: moved getResourceView to api out of server

swarm/storage/mru: Lookup algorithm working

swarm/storage/mru: comments and renamed NewLookupParams

Deleted commented code


swarm/storage/mru/lookup: renamed Epoch.LaterThan to After

swarm/storage/mru/lookup: Comments and tidying naming



swarm/storage/mru: fix lookup algorithm

swarm/storage/mru: exposed lookup hint
removed updateheader

swarm/storage/mru/lookup: changed GetNextEpoch for initial values

swarm/storage/mru: resource tests pass

swarm/storage/mru: valueSerializer interface and tests



swarm/storage/mru/lookup: Comments, improvements, fixes, more tests

swarm/storage/mru: renamed UpdateLookup to ID, LookupParams to Query

swarm/storage/mru: renamed query receiver var



swarm/cmd: MRU CLI tests

* cmd/swarm: remove rogue fmt

* swarm/storage/mru: Add version / header for future use

* swarm/storage/mru: Fixes/comments as per review

cmd/swarm: remove rogue fmt

swarm/storage/mru: Add version / header for future use-

* swarm/storage/mru: fix linter errors

* cmd/swarm: Speeded up TestCLIResourceUpdate
2018-09-28 12:07:17 +02:00

417 lines
18 KiB
Go

// Copyright 2018 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 lookup_test
import (
"fmt"
"math/rand"
"testing"
"github.com/ethereum/go-ethereum/swarm/log"
"github.com/ethereum/go-ethereum/swarm/storage/mru/lookup"
)
type Data struct {
Payload uint64
Time uint64
}
type Store map[lookup.EpochID]*Data
func write(store Store, epoch lookup.Epoch, value *Data) {
log.Debug("Write: %d-%d, value='%d'\n", epoch.Base(), epoch.Level, value.Payload)
store[epoch.ID()] = value
}
func update(store Store, last lookup.Epoch, now uint64, value *Data) lookup.Epoch {
var epoch lookup.Epoch
epoch = lookup.GetNextEpoch(last, now)
write(store, epoch, value)
return epoch
}
const Day = 60 * 60 * 24
const Year = Day * 365
const Month = Day * 30
func makeReadFunc(store Store, counter *int) lookup.ReadFunc {
return func(epoch lookup.Epoch, now uint64) (interface{}, error) {
*counter++
data := store[epoch.ID()]
var valueStr string
if data != nil {
valueStr = fmt.Sprintf("%d", data.Payload)
}
log.Debug("Read: %d-%d, value='%s'\n", epoch.Base(), epoch.Level, valueStr)
if data != nil && data.Time <= now {
return data, nil
}
return nil, nil
}
}
func TestLookup(t *testing.T) {
store := make(Store)
readCount := 0
readFunc := makeReadFunc(store, &readCount)
// write an update every month for 12 months 3 years ago and then silence for two years
now := uint64(1533799046)
var epoch lookup.Epoch
var lastData *Data
for i := uint64(0); i < 12; i++ {
t := uint64(now - Year*3 + i*Month)
data := Data{
Payload: t, //our "payload" will be the timestamp itself.
Time: t,
}
epoch = update(store, epoch, t, &data)
lastData = &data
}
// try to get the last value
value, err := lookup.Lookup(now, lookup.NoClue, readFunc)
if err != nil {
t.Fatal(err)
}
readCountWithoutHint := readCount
if value != lastData {
t.Fatalf("Expected lookup to return the last written value: %v. Got %v", lastData, value)
}
// reset the read count for the next test
readCount = 0
// Provide a hint to get a faster lookup. In particular, we give the exact location of the last update
value, err = lookup.Lookup(now, epoch, readFunc)
if err != nil {
t.Fatal(err)
}
if value != lastData {
t.Fatalf("Expected lookup to return the last written value: %v. Got %v", lastData, value)
}
if readCount > readCountWithoutHint {
t.Fatalf("Expected lookup to complete with fewer or same reads than %d since we provided a hint. Did %d reads.", readCountWithoutHint, readCount)
}
// try to get an intermediate value
// if we look for a value in now - Year*3 + 6*Month, we should get that value
// Since the "payload" is the timestamp itself, we can check this.
expectedTime := now - Year*3 + 6*Month
value, err = lookup.Lookup(expectedTime, lookup.NoClue, readFunc)
if err != nil {
t.Fatal(err)
}
data, ok := value.(*Data)
if !ok {
t.Fatal("Expected value to contain data")
}
if data.Time != expectedTime {
t.Fatalf("Expected value timestamp to be %d, got %d", data.Time, expectedTime)
}
}
func TestOneUpdateAt0(t *testing.T) {
store := make(Store)
readCount := 0
readFunc := makeReadFunc(store, &readCount)
now := uint64(1533903729)
var epoch lookup.Epoch
data := Data{
Payload: 79,
Time: 0,
}
update(store, epoch, 0, &data)
value, err := lookup.Lookup(now, lookup.NoClue, readFunc)
if err != nil {
t.Fatal(err)
}
if value != &data {
t.Fatalf("Expected lookup to return the last written value: %v. Got %v", data, value)
}
}
// Tests the update is found even when a bad hint is given
func TestBadHint(t *testing.T) {
store := make(Store)
readCount := 0
readFunc := makeReadFunc(store, &readCount)
now := uint64(1533903729)
var epoch lookup.Epoch
data := Data{
Payload: 79,
Time: 0,
}
// place an update for t=1200
update(store, epoch, 1200, &data)
// come up with some evil hint
badHint := lookup.Epoch{
Level: 18,
Time: 1200000000,
}
value, err := lookup.Lookup(now, badHint, readFunc)
if err != nil {
t.Fatal(err)
}
if value != &data {
t.Fatalf("Expected lookup to return the last written value: %v. Got %v", data, value)
}
}
func TestLookupFail(t *testing.T) {
store := make(Store)
readCount := 0
readFunc := makeReadFunc(store, &readCount)
now := uint64(1533903729)
// don't write anything and try to look up.
// we're testing we don't get stuck in a loop
value, err := lookup.Lookup(now, lookup.NoClue, readFunc)
if err != nil {
t.Fatal(err)
}
if value != nil {
t.Fatal("Expected value to be nil, since the update should've failed")
}
expectedReads := now/(1<<lookup.HighestLevel) + 1
if uint64(readCount) != expectedReads {
t.Fatalf("Expected lookup to fail after %d reads. Did %d reads.", expectedReads, readCount)
}
}
func TestHighFreqUpdates(t *testing.T) {
store := make(Store)
readCount := 0
readFunc := makeReadFunc(store, &readCount)
now := uint64(1533903729)
// write an update every second for the last 1000 seconds
var epoch lookup.Epoch
var lastData *Data
for i := uint64(0); i <= 994; i++ {
T := uint64(now - 1000 + i)
data := Data{
Payload: T, //our "payload" will be the timestamp itself.
Time: T,
}
epoch = update(store, epoch, T, &data)
lastData = &data
}
value, err := lookup.Lookup(lastData.Time, lookup.NoClue, readFunc)
if err != nil {
t.Fatal(err)
}
if value != lastData {
t.Fatalf("Expected lookup to return the last written value: %v. Got %v", lastData, value)
}
readCountWithoutHint := readCount
// reset the read count for the next test
readCount = 0
// Provide a hint to get a faster lookup. In particular, we give the exact location of the last update
value, err = lookup.Lookup(now, epoch, readFunc)
if err != nil {
t.Fatal(err)
}
if value != lastData {
t.Fatalf("Expected lookup to return the last written value: %v. Got %v", lastData, value)
}
if readCount > readCountWithoutHint {
t.Fatalf("Expected lookup to complete with fewer or equal reads than %d since we provided a hint. Did %d reads.", readCountWithoutHint, readCount)
}
for i := uint64(0); i <= 994; i++ {
T := uint64(now - 1000 + i) // update every second for the last 1000 seconds
value, err := lookup.Lookup(T, lookup.NoClue, readFunc)
if err != nil {
t.Fatal(err)
}
data, _ := value.(*Data)
if data == nil {
t.Fatalf("Expected lookup to return %d, got nil", T)
}
if data.Payload != T {
t.Fatalf("Expected lookup to return %d, got %d", T, data.Time)
}
}
}
func TestSparseUpdates(t *testing.T) {
store := make(Store)
readCount := 0
readFunc := makeReadFunc(store, &readCount)
// write an update every 5 years 3 times starting in Jan 1st 1970 and then silence
now := uint64(1533799046)
var epoch lookup.Epoch
var lastData *Data
for i := uint64(0); i < 5; i++ {
T := uint64(Year * 5 * i) // write an update every 5 years 3 times starting in Jan 1st 1970 and then silence
data := Data{
Payload: T, //our "payload" will be the timestamp itself.
Time: T,
}
epoch = update(store, epoch, T, &data)
lastData = &data
}
// try to get the last value
value, err := lookup.Lookup(now, lookup.NoClue, readFunc)
if err != nil {
t.Fatal(err)
}
readCountWithoutHint := readCount
if value != lastData {
t.Fatalf("Expected lookup to return the last written value: %v. Got %v", lastData, value)
}
// reset the read count for the next test
readCount = 0
// Provide a hint to get a faster lookup. In particular, we give the exact location of the last update
value, err = lookup.Lookup(now, epoch, readFunc)
if err != nil {
t.Fatal(err)
}
if value != lastData {
t.Fatalf("Expected lookup to return the last written value: %v. Got %v", lastData, value)
}
if readCount > readCountWithoutHint {
t.Fatalf("Expected lookup to complete with fewer reads than %d since we provided a hint. Did %d reads.", readCountWithoutHint, readCount)
}
}
// testG will hold precooked test results
// fields are abbreviated to reduce the size of the literal below
type testG struct {
e lookup.Epoch // last
n uint64 // next level
x uint8 // expected result
}
// test cases
var testGetNextLevelCases []testG = []testG{{e: lookup.Epoch{Time: 989875233, Level: 12}, n: 989875233, x: 11}, {e: lookup.Epoch{Time: 995807650, Level: 18}, n: 995598156, x: 19}, {e: lookup.Epoch{Time: 969167082, Level: 0}, n: 968990357, x: 18}, {e: lookup.Epoch{Time: 993087628, Level: 14}, n: 992987044, x: 20}, {e: lookup.Epoch{Time: 963364631, Level: 20}, n: 963364630, x: 19}, {e: lookup.Epoch{Time: 963497510, Level: 16}, n: 963370732, x: 18}, {e: lookup.Epoch{Time: 955421349, Level: 22}, n: 955421348, x: 21}, {e: lookup.Epoch{Time: 968220379, Level: 15}, n: 968220378, x: 14}, {e: lookup.Epoch{Time: 939129014, Level: 6}, n: 939128771, x: 11}, {e: lookup.Epoch{Time: 907847903, Level: 6}, n: 907791833, x: 18}, {e: lookup.Epoch{Time: 910835564, Level: 15}, n: 910835564, x: 14}, {e: lookup.Epoch{Time: 913578333, Level: 22}, n: 881808431, x: 25}, {e: lookup.Epoch{Time: 895818460, Level: 3}, n: 895818132, x: 9}, {e: lookup.Epoch{Time: 903843025, Level: 24}, n: 895609561, x: 23}, {e: lookup.Epoch{Time: 877889433, Level: 13}, n: 877877093, x: 15}, {e: lookup.Epoch{Time: 901450396, Level: 10}, n: 901450058, x: 9}, {e: lookup.Epoch{Time: 925179910, Level: 3}, n: 925168393, x: 16}, {e: lookup.Epoch{Time: 913485477, Level: 21}, n: 913485476, x: 20}, {e: lookup.Epoch{Time: 924462991, Level: 18}, n: 924462990, x: 17}, {e: lookup.Epoch{Time: 941175128, Level: 13}, n: 941175127, x: 12}, {e: lookup.Epoch{Time: 920126583, Level: 3}, n: 920100782, x: 19}, {e: lookup.Epoch{Time: 932403200, Level: 9}, n: 932279891, x: 17}, {e: lookup.Epoch{Time: 948284931, Level: 2}, n: 948284921, x: 9}, {e: lookup.Epoch{Time: 953540997, Level: 7}, n: 950547986, x: 22}, {e: lookup.Epoch{Time: 926639837, Level: 18}, n: 918608882, x: 24}, {e: lookup.Epoch{Time: 954637598, Level: 1}, n: 954578761, x: 17}, {e: lookup.Epoch{Time: 943482981, Level: 10}, n: 942924151, x: 19}, {e: lookup.Epoch{Time: 963580771, Level: 7}, n: 963580771, x: 6}, {e: lookup.Epoch{Time: 993744930, Level: 7}, n: 993690858, x: 16}, {e: lookup.Epoch{Time: 1018890213, Level: 12}, n: 1018890212, x: 11}, {e: lookup.Epoch{Time: 1030309411, Level: 2}, n: 1030309227, x: 9}, {e: lookup.Epoch{Time: 1063204997, Level: 20}, n: 1063204996, x: 19}, {e: lookup.Epoch{Time: 1094340832, Level: 6}, n: 1094340633, x: 7}, {e: lookup.Epoch{Time: 1077880597, Level: 10}, n: 1075914292, x: 20}, {e: lookup.Epoch{Time: 1051114957, Level: 18}, n: 1051114957, x: 17}, {e: lookup.Epoch{Time: 1045649701, Level: 22}, n: 1045649700, x: 21}, {e: lookup.Epoch{Time: 1066198885, Level: 14}, n: 1066198884, x: 13}, {e: lookup.Epoch{Time: 1053231952, Level: 1}, n: 1053210845, x: 16}, {e: lookup.Epoch{Time: 1068763404, Level: 14}, n: 1068675428, x: 18}, {e: lookup.Epoch{Time: 1039042173, Level: 15}, n: 1038973110, x: 17}, {e: lookup.Epoch{Time: 1050747636, Level: 6}, n: 1050747364, x: 9}, {e: lookup.Epoch{Time: 1030034434, Level: 23}, n: 1030034433, x: 22}, {e: lookup.Epoch{Time: 1003783425, Level: 18}, n: 1003783424, x: 17}, {e: lookup.Epoch{Time: 988163976, Level: 15}, n: 988084064, x: 17}, {e: lookup.Epoch{Time: 1007222377, Level: 15}, n: 1007222377, x: 14}, {e: lookup.Epoch{Time: 1001211375, Level: 13}, n: 1001208178, x: 14}, {e: lookup.Epoch{Time: 997623199, Level: 8}, n: 997623198, x: 7}, {e: lookup.Epoch{Time: 1026283830, Level: 10}, n: 1006681704, x: 24}, {e: lookup.Epoch{Time: 1019421907, Level: 20}, n: 1019421906, x: 19}, {e: lookup.Epoch{Time: 1043154306, Level: 16}, n: 1043108343, x: 16}, {e: lookup.Epoch{Time: 1075643767, Level: 17}, n: 1075325898, x: 18}, {e: lookup.Epoch{Time: 1043726309, Level: 20}, n: 1043726308, x: 19}, {e: lookup.Epoch{Time: 1056415324, Level: 17}, n: 1056415324, x: 16}, {e: lookup.Epoch{Time: 1088650219, Level: 13}, n: 1088650218, x: 12}, {e: lookup.Epoch{Time: 1088551662, Level: 7}, n: 1088543355, x: 13}, {e: lookup.Epoch{Time: 1069667265, Level: 6}, n: 1069667075, x: 7}, {e: lookup.Epoch{Time: 1079145970, Level: 18}, n: 1079145969, x: 17}, {e: lookup.Epoch{Time: 1083338876, Level: 7}, n: 1083338875, x: 6}, {e: lookup.Epoch{Time: 1051581086, Level: 4}, n: 1051568869, x: 14}, {e: lookup.Epoch{Time: 1028430882, Level: 4}, n: 1028430864, x: 5}, {e: lookup.Epoch{Time: 1057356462, Level: 1}, n: 1057356417, x: 5}, {e: lookup.Epoch{Time: 1033104266, Level: 0}, n: 1033097479, x: 13}, {e: lookup.Epoch{Time: 1031391367, Level: 11}, n: 1031387304, x: 14}, {e: lookup.Epoch{Time: 1049781164, Level: 15}, n: 1049781163, x: 14}, {e: lookup.Epoch{Time: 1027271628, Level: 12}, n: 1027271627, x: 11}, {e: lookup.Epoch{Time: 1057270560, Level: 23}, n: 1057270560, x: 22}, {e: lookup.Epoch{Time: 1047501317, Level: 15}, n: 1047501317, x: 14}, {e: lookup.Epoch{Time: 1058349035, Level: 11}, n: 1045175573, x: 24}, {e: lookup.Epoch{Time: 1057396147, Level: 20}, n: 1057396147, x: 19}, {e: lookup.Epoch{Time: 1048906375, Level: 18}, n: 1039616919, x: 25}, {e: lookup.Epoch{Time: 1074294831, Level: 20}, n: 1074294831, x: 19}, {e: lookup.Epoch{Time: 1088946052, Level: 1}, n: 1088917364, x: 14}, {e: lookup.Epoch{Time: 1112337595, Level: 17}, n: 1111008110, x: 22}, {e: lookup.Epoch{Time: 1099990284, Level: 5}, n: 1099968370, x: 15}, {e: lookup.Epoch{Time: 1087036441, Level: 16}, n: 1053967855, x: 25}, {e: lookup.Epoch{Time: 1069225185, Level: 8}, n: 1069224660, x: 10}, {e: lookup.Epoch{Time: 1057505479, Level: 9}, n: 1057505170, x: 14}, {e: lookup.Epoch{Time: 1072381377, Level: 12}, n: 1065950959, x: 22}, {e: lookup.Epoch{Time: 1093887139, Level: 8}, n: 1093863305, x: 14}, {e: lookup.Epoch{Time: 1082366510, Level: 24}, n: 1082366510, x: 23}, {e: lookup.Epoch{Time: 1103231132, Level: 14}, n: 1102292201, x: 22}, {e: lookup.Epoch{Time: 1094502355, Level: 3}, n: 1094324652, x: 18}, {e: lookup.Epoch{Time: 1068488344, Level: 12}, n: 1067577330, x: 19}, {e: lookup.Epoch{Time: 1050278233, Level: 12}, n: 1050278232, x: 11}, {e: lookup.Epoch{Time: 1047660768, Level: 5}, n: 1047652137, x: 17}, {e: lookup.Epoch{Time: 1060116167, Level: 11}, n: 1060114091, x: 12}, {e: lookup.Epoch{Time: 1068149392, Level: 21}, n: 1052074801, x: 24}, {e: lookup.Epoch{Time: 1081934120, Level: 6}, n: 1081933847, x: 8}, {e: lookup.Epoch{Time: 1107943693, Level: 16}, n: 1107096139, x: 25}, {e: lookup.Epoch{Time: 1131571649, Level: 9}, n: 1131570428, x: 11}, {e: lookup.Epoch{Time: 1123139367, Level: 0}, n: 1122912198, x: 20}, {e: lookup.Epoch{Time: 1121144423, Level: 6}, n: 1120568289, x: 20}, {e: lookup.Epoch{Time: 1089932411, Level: 17}, n: 1089932410, x: 16}, {e: lookup.Epoch{Time: 1104899012, Level: 22}, n: 1098978789, x: 22}, {e: lookup.Epoch{Time: 1094588059, Level: 21}, n: 1094588059, x: 20}, {e: lookup.Epoch{Time: 1114987438, Level: 24}, n: 1114987437, x: 23}, {e: lookup.Epoch{Time: 1084186305, Level: 7}, n: 1084186241, x: 6}, {e: lookup.Epoch{Time: 1058827111, Level: 8}, n: 1058826504, x: 9}, {e: lookup.Epoch{Time: 1090679810, Level: 12}, n: 1090616539, x: 17}, {e: lookup.Epoch{Time: 1084299475, Level: 23}, n: 1084299475, x: 22}}
func TestGetNextLevel(t *testing.T) {
// First, test well-known cases
last := lookup.Epoch{
Time: 1533799046,
Level: 5,
}
level := lookup.GetNextLevel(last, last.Time)
expected := uint8(4)
if level != expected {
t.Fatalf("Expected GetNextLevel to return %d for same-time updates at a nonzero level, got %d", expected, level)
}
level = lookup.GetNextLevel(last, last.Time+(1<<lookup.HighestLevel)+3000)
expected = lookup.HighestLevel
if level != expected {
t.Fatalf("Expected GetNextLevel to return %d for updates set 2^lookup.HighestLevel seconds away, got %d", expected, level)
}
level = lookup.GetNextLevel(last, last.Time+(1<<last.Level))
expected = last.Level
if level != expected {
t.Fatalf("Expected GetNextLevel to return %d for updates set 2^last.Level seconds away, got %d", expected, level)
}
last.Level = 0
level = lookup.GetNextLevel(last, last.Time)
expected = 0
if level != expected {
t.Fatalf("Expected GetNextLevel to return %d for same-time updates at a zero level, got %d", expected, level)
}
// run a batch of 100 cooked tests
for _, s := range testGetNextLevelCases {
level := lookup.GetNextLevel(s.e, s.n)
if level != s.x {
t.Fatalf("Expected GetNextLevel to return %d for last=%s when now=%d, got %d", s.x, s.e.String(), s.n, level)
}
}
}
// cookGetNextLevelTests is used to generate a deterministic
// set of cases for TestGetNextLevel and thus "freeze" its current behavior
func CookGetNextLevelTests(t *testing.T) {
st := ""
var last lookup.Epoch
last.Time = 1000000000
var now uint64
var expected uint8
for i := 0; i < 100; i++ {
last.Time += uint64(rand.Intn(1<<26)) - (1 << 25)
last.Level = uint8(rand.Intn(25))
v := last.Level + uint8(rand.Intn(lookup.HighestLevel))
if v > lookup.HighestLevel {
v = 0
}
now = last.Time + uint64(rand.Intn(1<<v+1)) - (1 << v)
expected = lookup.GetNextLevel(last, now)
st = fmt.Sprintf("%s,testG{e:lookup.Epoch{Time:%d, Level:%d}, n:%d, x:%d}", st, last.Time, last.Level, now, expected)
}
fmt.Println(st)
}