fix(tests): added tests for DHT

db.go

@@ -78,8 +78,8 @@ func (db *DB) NewDHT(dbs ...int) {
 	db.dht = shardid.NewDHT(dbs...)
 }
 
-// AddDHT add new databases into current DHT
-func (db *DB) AddDHT(dbs ...int) {
+// DHTAdd add new databases into current DHT
+func (db *DB) DHTAdd(dbs ...int) {
 	db.Lock()
 	defer db.Unlock()
 	if db.dht == nil {
@@ -88,14 +88,14 @@ func (db *DB) AddDHT(dbs ...int) {
 	db.dht.Add(dbs...)
 }
 
-// EndDHT end current DHT scaling, and reload.
-func (db *DB) EndDHT() {
+// DHTAdded get databases added on current DHT, and reload it.
+func (db *DB) DHTAdded() {
 	db.Lock()
 	defer db.Unlock()
 	if db.dht == nil {
 		return
 	}
-	db.dht.End()
+	db.dht.Done()
 }
 
 // OnDHT select database from DHT

db_test.go

@@ -83,6 +83,25 @@ func TestOn(t *testing.T) {
 
 }
 
+func TestDHT(t *testing.T) {
+	db := Open(createSQLite3())
+
+	// always work if only single server
+	ctx, err := db.OnDHT("")
+	require.Equal(t, 0, ctx.index)
+	require.Nil(t, err)
+
+	// MUST NOT panic even DHT is missing
+	db.DHTAdd(1)
+	db.DHTAdded()
+
+	db.Add(createSQLite3())
+
+	ctx, err = db.OnDHT("")
+	require.ErrorIs(t, err, ErrMissingDHT)
+	require.Nil(t, ctx)
+}
+
 func TestOnDHT(t *testing.T) {
 	dbs := make([]*sql.DB, 0, 10)
 
@@ -240,7 +259,7 @@ func TestDHTScaling(t *testing.T) {
 		require.Equal(t, it.current, ctx.index)
 	}
 
-	db.AddDHT(2)
+	db.DHTAdd(2)
 
 	for v, it := range values {
 		ctx, err := db.OnDHT(v)
@@ -253,7 +272,7 @@ func TestDHTScaling(t *testing.T) {
 
 	}
 
-	db.EndDHT()
+	db.DHTAdded()
 	for v, it := range values {
 		ctx, err := db.OnDHT(v)
 		require.NoError(t, err)

shardid/dht.go

@@ -33,7 +33,7 @@ func NewDHT(dbs ...int) *DHT {
 		m.dbs[i] = db
 	}
 
-	m.current = NewHR(m.dbsCount)
+	m.current = NewHR(m.dbsCount, WithReplicas(defaultReplicas...))
 
 	return m
 }
@@ -60,8 +60,8 @@ func (m *DHT) On(v string) (int, int, error) {
 	return current, current, nil
 }
 
-// End end added, and reset current and next HashRings
-func (m *DHT) End() {
+// Done dbs are added, then reset current/next HashRing
+func (m *DHT) Done() {
 	m.Lock()
 	defer m.Unlock()
 
@@ -81,7 +81,7 @@ func (m *DHT) Add(dbs ...int) []int {
 	}
 
 	m.dbsCount += len(dbs)
-	m.next = NewHR(m.dbsCount)
+	m.next = NewHR(m.dbsCount, WithReplicas(defaultReplicas...))
 	var (
 		db1 int
 		db2 int

shardid/dht_test.go

@@ -113,7 +113,7 @@ func TestDHT(t *testing.T) {
 	require.Equal(t, 1, next)
 	require.Nil(t, err) // > Q1 last node => E0!
 
-	m.End()
+	m.Done()
 
 	cur, next, err = m.On("E1")
 	require.Equal(t, 3, cur)