util: fix unit test

util/chunk/chunk.go

@@ -77,24 +77,30 @@ func New(fields []*types.FieldType, cap, maxChunkSize int) *Chunk {
 	return chk
 }
 
-// Renew creates a new Chunk based on an existing Chunk. The newly created Chunk
-// has the same data schema with the old Chunk. The capacity of the new Chunk
-// might be doubled based on the capacity of the old Chunk and the maxChunkSize.
-//  chk: old chunk(often used in previous call).
-//  maxChunkSize: the limit for the max number of rows.
-func Renew(chk *Chunk, maxChunkSize int) *Chunk {
+// renewWithCapacity creates a new Chunk based on an existing Chunk with capacity. The newly
+// created Chunk has the same data schema with the old Chunk.
+func renewWithCapacity(chk *Chunk, cap, maxChunkSize int) *Chunk {
 	newChk := new(Chunk)
 	if chk.columns == nil {
 		return newChk
 	}
-	newCap := reCalcCapacity(chk, maxChunkSize)
-	newChk.columns = renewColumns(chk.columns, newCap)
+	newChk.columns = renewColumns(chk.columns, cap)
 	newChk.numVirtualRows = 0
-	newChk.capacity = newCap
+	newChk.capacity = cap
 	newChk.requiredRows = maxChunkSize
 	return newChk
 }
 
+// Renew creates a new Chunk based on an existing Chunk. The newly created Chunk
+// has the same data schema with the old Chunk. The capacity of the new Chunk
+// might be doubled based on the capacity of the old Chunk and the maxChunkSize.
+//  chk: old chunk(often used in previous call).
+//  maxChunkSize: the limit for the max number of rows.
+func Renew(chk *Chunk, maxChunkSize int) *Chunk {
+	newCap := reCalcCapacity(chk, maxChunkSize)
+	return renewWithCapacity(chk, newCap, maxChunkSize)
+}
+
 // renewColumns creates the columns of a Chunk. The capacity of the newly
 // created columns is equal to cap.
 func renewColumns(oldCol []*column, cap int) []*column {

util/chunk/row.go

@@ -222,3 +222,10 @@ func (r Row) GetDatum(colIdx int, tp *types.FieldType) types.Datum {
 func (r Row) IsNull(colIdx int) bool {
 	return r.c.columns[colIdx].isNull(r.idx)
 }
+
+// CopyConstruct creates a new row and copies this row's data into it.
+func (r Row) CopyConstruct() Row {
+	newChk := renewWithCapacity(r.c, 1, 1)
+	newChk.AppendRow(r)
+	return newChk.GetRow(0)
+}