fix: unit-test failed

core/blockchain_diff_test.go

@@ -280,10 +280,14 @@ func TestFreezeDiffLayer(t *testing.T) {
 	blockNum := 1024
 	fullBackend := newTestBackend(blockNum, true)
 	defer fullBackend.close()
+	for len(fullBackend.chain.diffQueueBuffer) > 0 {
+		// Wait for the buffer to be zero.
+	}
 	// Minus one empty block.
 	if fullBackend.chain.diffQueue.Size() != blockNum-1 {
-		t.Errorf("size of diff queue is wrong, expected: %d, get: %d", blockNum, fullBackend.chain.diffQueue.Size())
+		t.Errorf("size of diff queue is wrong, expected: %d, get: %d", blockNum-1, fullBackend.chain.diffQueue.Size())
 	}
+
 	time.Sleep(diffLayerFreezerRecheckInterval + 1*time.Second)
 	if fullBackend.chain.diffQueue.Size() != int(fullBackend.chain.triesInMemory) {
 		t.Errorf("size of diff queue is wrong, expected: %d, get: %d", blockNum, fullBackend.chain.diffQueue.Size())