multi: repo-wide bandaid for rand.Seed abuses

Early on we got in the habit of building tests on data with reproducible
random sequences using the math/rand package's global *math.Rand
instance, seeding it with some arbitrary hard coded numbers to get
certain sequence. That proved quite problematic for test maintenance,
concurrency, and now the standard library rightly has deprecated the use
of rand.Seed and they have made the default initialization actually
random instead of with "1" as the seed.

> The math/rand package now automatically seeds the global random number
> generator (used by top-level functions like Float64 and Int) with a
> random value, and the top-level Seed function has been deprecated.
> Programs that need a reproducible sequence of random numbers should
> prefer to allocate their own random source, using
> rand.New(rand.NewSource(seed)).
>
> Programs that need the earlier consistent global seeding behavior can
> set GODEBUG=randautoseed=0 in their environment.
>
> The top-level Read function has been deprecated. In almost all cases,
> crypto/rand.Read is more appropriate.

This commit is a bandaid to get the test passing given the new random
seeding of the package level math/rand.Rand. We should look at rewriting
some of these tests to not have unrecorded but expected magic values to
produce certain test data set.

client/db/bolt/db_test.go

@@ -20,10 +20,6 @@ import (
 	"go.etcd.io/bbolt"
 )
 
-func init() {
-	rand.Seed(time.Now().UnixNano())
-}
-
 var (
 	tLogger = dex.StdOutLogger("db_TEST", dex.LevelTrace)
 )

dex/order/match_test.go

@@ -8,14 +8,13 @@ import (
 	"time"
 )
 
-// randomCommitment creates a random order commitment. If you require a matching
-// commitment, generate a Preimage, then Preimage.Commit().
-func randomCommitment() (com Commitment) {
-	rand.Read(com[:])
-	return
-}
-
 func TestMatchID(t *testing.T) {
+	rnd := rand.New(rand.NewSource(1))
+	randomCommitment := func() (com Commitment) {
+		rnd.Read(com[:])
+		return
+	}
+
 	// taker
 	marketID0, _ := hex.DecodeString("f1f4fb29235f5eeef55b27d909aac860828f6cf45f0b0fab92c6265844c50e54")
 	var marketID OrderID

dex/order/test/helpers.go

@@ -2,6 +2,7 @@ package test
 
 import (
 	"bytes"
+	crand "crypto/rand"
 	"encoding/binary"
 	"fmt"
 	"math/rand"
@@ -18,6 +19,34 @@ const (
 	addressLength  = 34
 )
 
+var rnd = rand.New(CryptoSource)
+
+func UseRand(use *rand.Rand) {
+	rnd = use
+}
+
+var CryptoSource cryptoSource
+
+type cryptoSource struct{}
+
+func (cs cryptoSource) Uint64() uint64 {
+	var b [8]byte
+	crand.Read(b[:])
+	return binary.LittleEndian.Uint64(b[:])
+}
+
+func (cs cryptoSource) Int63() int64 {
+	const rngMask = 1<<63 - 1
+	return int64(cs.Uint64() & rngMask)
+}
+
+func (cs cryptoSource) Seed(seed int64) { /* no-op */ }
+
+var _ rand.Source = cryptoSource{}
+var _ rand.Source = (*cryptoSource)(nil)
+var _ rand.Source64 = cryptoSource{}
+var _ rand.Source64 = (*cryptoSource)(nil)
+
 var (
 	acctTemplate = account.AccountID{
 		0x22, 0x4c, 0xba, 0xaa, 0xfa, 0x80, 0xbf, 0x3b, 0xd1, 0xff, 0x73, 0x15,
@@ -29,22 +58,22 @@ var (
 
 func randBytes(l int) []byte {
 	b := make([]byte, l)
-	rand.Read(b)
+	rnd.Read(b)
 	return b
 }
 
-func randUint32() uint32 { return uint32(rand.Int31()) }
-func randUint64() uint64 { return uint64(rand.Int63()) }
+func randUint32() uint32 { return uint32(rnd.Int31()) }
+func randUint64() uint64 { return uint64(rnd.Int63()) }
 
 func randBool() bool {
-	return rand.Intn(2) == 1
+	return rnd.Intn(2) == 1
 }
 
 // A random base-58 string.
 func RandomAddress() string {
 	b := make([]byte, addressLength)
 	for i := range b {
-		b[i] = b58Set[rand.Intn(58)]
+		b[i] = b58Set[rnd.Intn(58)]
 	}
 	return string(b)
 }
@@ -76,14 +105,14 @@ func RandomMatchID() order.MatchID {
 
 // RandomPreimage creates a random order preimage.
 func RandomPreimage() (pi order.Preimage) {
-	rand.Read(pi[:])
+	rnd.Read(pi[:])
 	return
 }
 
 // RandomCommitment creates a random order commitment. Use RandomPreimage
 // followed by Preimage.Commit() if you require a matching commitment.
 func RandomCommitment() (com order.Commitment) {
-	rand.Read(com[:])
+	rnd.Read(com[:])
 	return
 }
 
@@ -143,7 +172,7 @@ func WriteLimitOrder(writer *Writer, rate, lots uint64, force order.TimeInForce,
 
 // RandomLimitOrder creates a random limit order with a random writer.
 func RandomLimitOrder() (*order.LimitOrder, order.Preimage) {
-	return WriteLimitOrder(RandomWriter(), randUint64(), randUint64(), order.TimeInForce(rand.Intn(2)), 0)
+	return WriteLimitOrder(RandomWriter(), randUint64(), randUint64(), order.TimeInForce(rnd.Intn(2)), 0)
 }
 
 // WriteMarketOrder creates a market order with the specified writer and
@@ -255,8 +284,8 @@ func RandomUserMatch() *order.UserMatch {
 		Quantity:    randUint64(),
 		Rate:        randUint64(),
 		Address:     RandomAddress(),
-		Status:      order.MatchStatus(rand.Intn(5)),
-		Side:        order.MatchSide(rand.Intn(2)),
+		Status:      order.MatchStatus(rnd.Intn(5)),
+		Side:        order.MatchSide(rnd.Intn(2)),
 		FeeRateSwap: randUint64(),
 	}
 }

server/auth/cancel_test.go

@@ -1,6 +1,7 @@
 package auth
 
 import (
+	crand "crypto/rand"
 	"math/rand"
 	"sort"
 	"testing"
@@ -9,7 +10,7 @@ import (
 )
 
 func randomOrderID() (oid order.OrderID) {
-	rand.Read(oid[:])
+	crand.Read(oid[:])
 	return
 }
 
@@ -79,8 +80,6 @@ func Test_latestOrders(t *testing.T) {
 		t.Errorf("expected 1 cancels, got %d", total)
 	}
 
-	rand.Seed(1324)
-
 	for i := total; i < int(cap); i++ {
 		ts++
 		ordList.add(&oidStamped{

server/book/orderpq_test.go

@@ -3,6 +3,7 @@ package book
 import (
 	"flag"
 	"math/rand"
+	crand "math/rand"
 	"os"
 	"sort"
 	"testing"
@@ -15,25 +16,20 @@ type Order = order.LimitOrder
 
 var (
 	bigList []*Order
-	orders  = []*Order{
-		newLimitOrder(false, 42000000, 2, order.StandingTiF, 0),
-		newLimitOrder(false, 10000, 2, order.StandingTiF, 0),
-		newLimitOrder(false, 42000000, 2, order.StandingTiF, -1000), // rate dup, different time
-		newLimitOrder(false, 123000000, 2, order.StandingTiF, 0),
-		newLimitOrder(false, 42000000, 1, order.StandingTiF, 0), // rate and time dup, different OrderID
-	}
+	orders  []*Order
+	rnd     = rand.New(rand.NewSource(1))
 )
 
 func randomAccount() (user account.AccountID) {
-	rand.Read(user[:])
+	crand.Read(user[:])
 	return
 }
 
 func newFakeAddr() string {
 	const letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
 	b := make([]byte, 35)
 	for i := range b {
-		b[i] = letters[rand.Int63()%int64(len(letters))]
+		b[i] = letters[rnd.Int63()%int64(len(letters))]
 	}
 	b[0], b[1] = 'D', 's' // at least have it resemble an address
 	return string(b)
@@ -44,7 +40,7 @@ func genBigList(listSize int) {
 		return
 	}
 	seed := int64(-3405439173988651889)
-	rand.Seed(seed)
+	rnd.Seed(seed)
 
 	dupRate := 800
 	if listSize < dupRate {
@@ -56,7 +52,7 @@ func genBigList(listSize int) {
 
 	bigList = make([]*Order, 0, listSize)
 	for i := 0; i < listSize; i++ {
-		lo := newLimitOrder(false, uint64(rand.Int63n(90000000)), uint64(rand.Int63n(6))+1, order.StandingTiF, rand.Int63n(240)-120)
+		lo := newLimitOrder(false, uint64(rnd.Int63n(90000000)), uint64(rnd.Int63n(6))+1, order.StandingTiF, rnd.Int63n(240)-120)
 		lo.Address = newFakeAddr()
 		// duplicate some prices
 		if (i+1)%(listSize/dupRate) == 0 {
@@ -75,6 +71,14 @@ const (
 
 func TestMain(m *testing.M) {
 	flag.Parse() // for -short
+	rnd.Seed(4)  // some predetermined and reproducible order IDs
+	orders = []*Order{
+		newLimitOrder(false, 42000000, 2, order.StandingTiF, 0),
+		newLimitOrder(false, 10000, 2, order.StandingTiF, 0),
+		newLimitOrder(false, 42000000, 2, order.StandingTiF, -1000), // rate dup, different time
+		newLimitOrder(false, 123000000, 2, order.StandingTiF, 0),
+		newLimitOrder(false, 42000000, 1, order.StandingTiF, 0), // rate and time dup, different OrderID
+	}
 	if testing.Short() {
 		genBigList(shortListLen)
 	} else {
@@ -419,13 +423,13 @@ func TestMaxOrderPQ_TieRate(t *testing.T) {
 func TestMaxOrderPQ_TieRateAndTime(t *testing.T) {
 	pq := NewMaxOrderPQ(4)
 
-	// 7f9200eedcf2fa868173cdfc2101ee4d71ec024c1c052589b3371442aaa26c2d
+	// 3671433862ea385f967377d836040cfa74bd66cf35ee1795cc48cab2a9576bc1
 	ok := pq.Insert(orders[0])
 	if !ok {
 		t.Errorf("Failed to insert order %v", orders[0])
 	}
 
-	// 2eb563f255b0a9484bbbee718b2cdce3a31bd5ea8649b579b3184a4bd60d1703 ** higher priority
+	// 1cc5fe0804be6b8112b71dd2d8d4a48177ee78a7f2c663e620c369d3211c86a1 ** higher priority
 	ok = pq.Insert(orders[4])
 	if !ok {
 		t.Errorf("Failed to insert order %v", orders[4])

server/coinlock/coinlocker_test.go

@@ -1,6 +1,7 @@
 package coinlock
 
 import (
+	crand "crypto/rand"
 	"math/rand"
 	"testing"
 
@@ -10,7 +11,7 @@ import (
 
 func randomBytes(len int) []byte {
 	bytes := make([]byte, len)
-	rand.Read(bytes)
+	crand.Read(bytes)
 	return bytes
 }
 
@@ -50,8 +51,6 @@ func verifyLocked(cl CoinLockChecker, coins []CoinID, wantLocked bool, t *testin
 }
 
 func Test_swapLocker_LockOrderCoins(t *testing.T) {
-	rand.Seed(0)
-
 	w := &test.Writer{
 		Addr: "asdf",
 		Acct: test.NextAccount(),
@@ -146,8 +145,6 @@ func Test_bookLocker_LockCoins(t *testing.T) {
 	masterLock := NewMasterCoinLocker()
 	bookLock := masterLock.Book()
 
-	rand.Seed(0)
-
 	coinMap := make(map[order.OrderID][]CoinID)
 	var allCoins []CoinID
 	numOrders := 99

server/market/integ/booker_matcher_test.go

@@ -23,6 +23,8 @@ var acct0 = account.AccountID{
 	0x46, 0x34, 0xe9, 0x1c, 0xec, 0x25, 0xd5, 0x40, // 32 bytes
 }
 
+var rnd = rand.New(rand.NewSource(1))
+
 const (
 	AssetDCR uint32 = iota
 	AssetBTC
@@ -39,7 +41,7 @@ func startLogger() {
 }
 
 func randomPreimage() (pe order.Preimage) {
-	rand.Read(pe[:])
+	rnd.Read(pe[:])
 	return
 }
 
@@ -243,7 +245,7 @@ func TestMatchWithBook_limitsOnly(t *testing.T) {
 	// New matching engine.
 	me := matcher.New()
 
-	rand.Seed(0)
+	rnd.Seed(0)
 
 	badLotsizeOrder := newLimit(false, 05000000, 1, order.ImmediateTiF, 0)
 	badLotsizeOrder.Order.(*order.LimitOrder).Quantity /= 2
@@ -497,7 +499,7 @@ func TestMatchWithBook_limitsOnly_multipleQueued(t *testing.T) {
 	// New matching engine.
 	me := matcher.New()
 
-	rand.Seed(0)
+	rnd.Seed(0)
 
 	// epochQueue is heterogenous w.r.t. type
 	epochQueue := []*matcher.OrderRevealed{
@@ -731,7 +733,7 @@ func TestMatch_cancelOnly(t *testing.T) {
 	// New matching engine.
 	me := matcher.New()
 
-	rand.Seed(0)
+	rnd.Seed(0)
 
 	fakeOrder := newLimitOrder(false, 4550000, 1, order.ImmediateTiF, 0)
 	fakeOrder.ServerTime = time.Unix(1566497654, 0)
@@ -861,7 +863,7 @@ func TestMatch_marketSellsOnly(t *testing.T) {
 	// New matching engine.
 	me := matcher.New()
 
-	rand.Seed(0)
+	rnd.Seed(0)
 
 	badLotsizeOrder := newMarketSell(1, 0)
 	badLotsizeOrder.Order.(*order.MarketOrder).Quantity /= 2
@@ -1116,7 +1118,7 @@ func TestMatch_marketBuysOnly(t *testing.T) {
 	// New matching engine.
 	me := matcher.New()
 
-	rand.Seed(0)
+	rnd.Seed(0)
 
 	nSell := len(bookSellOrders)
 	//nBuy := len(bookBuyOrders)
@@ -1291,7 +1293,7 @@ func TestMatchWithBook_everything_multipleQueued(t *testing.T) {
 	// New matching engine.
 	me := matcher.New()
 
-	rand.Seed(12)
+	rnd.Seed(12)
 
 	nSell := len(bookSellOrders)
 	nBuy := len(bookBuyOrders)