[trie] test leaf node (#3672)

* add leafnode

* modify upsert test

* add case

* add special case

* add special case

* modify comment

* format

* resolve conflict

Co-authored-by: Raullen Chai <raullenchai@gmail.com>

db/trie/mptrie/leafnode_test.go

@@ -0,0 +1,170 @@
+// Copyright (c) 2020 IoTeX Foundation
+// This is an alpha (internal) release and is not suitable for production. This source code is provided 'as is' and no
+// warranties are given as to title or non-infringement, merchantability or fitness for purpose and, to the extent
+// permitted by law, all liability for your use of the code is disclaimed. This source code is governed by Apache
+// License 2.0 that can be found in the LICENSE file.
+
+package mptrie
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/iotexproject/iotex-core/db/trie"
+	"github.com/iotexproject/iotex-core/db/trie/triepb"
+)
+
+func TestLeafNodeProto(t *testing.T) {
+	require := require.New(t)
+	lnode := &leafNode{
+		key:   []byte("iotex"),
+		value: []byte("chain"),
+	}
+	proto, err := lnode.proto(nil, true)
+	require.NoError(err)
+	nodepb, ok := proto.(*triepb.NodePb)
+	require.True(ok)
+	leaf, ok := nodepb.Node.(*triepb.NodePb_Leaf)
+	require.True(ok)
+	lnode1 := newLeafNodeFromProtoPb(leaf.Leaf, nil)
+	require.Equal(lnode.key, lnode1.key)
+	require.Equal(lnode.value, lnode1.value)
+}
+
+func TestLeafOperation(t *testing.T) {
+	var (
+		require = require.New(t)
+		cli     = &merklePatriciaTrie{
+			hashFunc: DefaultHashFunc,
+			kvStore:  trie.NewMemKVStore(),
+		}
+	)
+
+	// create
+	node, err := newLeafNode(cli, keyType("iotex"), []byte("coin"))
+	require.NoError(err)
+
+	// leaf.Upsert newLeafNode -> leaf
+	node, err = node.Upsert(cli, keyType("iotex"), 0, []byte("chain"))
+	require.NoError(err)
+	leaf, ok := node.(*leafNode)
+	require.True(ok)
+	require.Equal(keyType("iotex"), leaf.key)
+	require.Equal([]byte("chain"), leaf.value)
+
+	// leaf.Upsert newBranchNode -> branch
+	node, err = node.Upsert(cli, keyType("block"), 0, []byte("chain"))
+	require.NoError(err)
+	bnode, ok := node.(*branchNode)
+	require.True(ok)
+	require.Len(bnode.children, 2)
+	checkLeaf(require, bnode, keyType("iotex"), 0, []byte("chain"))
+	checkLeaf(require, bnode, keyType("block"), 0, []byte("chain"))
+
+	// branch.Upsert child.Upsert -> leaf.Upsert newExtensionNode -> extension
+	node, err = node.Upsert(cli, keyType("ioabc123"), 0, []byte("chabc"))
+	require.NoError(err)
+	bnode, ok = node.(*branchNode)
+	require.True(ok)
+	require.Len(bnode.children, 2)
+	enode, ok := bnode.children[byte('i')].(*extensionNode)
+	require.True(ok)
+	require.Equal([]byte("o"), enode.path)
+	bnode, ok = enode.child.(*branchNode)
+	require.True(ok)
+	require.Len(bnode.children, 2)
+	checkLeaf(require, bnode, keyType("iotex"), 2, []byte("chain"))
+	checkLeaf(require, bnode, keyType("ioabc123"), 2, []byte("chabc"))
+
+	// branch.Upsert child.Upsert -> branch
+	node, err = node.Upsert(cli, keyType("ixy"), 0, []byte("dog"))
+	require.NoError(err)
+	bnode, ok = node.(*branchNode)
+	require.True(ok)
+	require.Len(bnode.children, 2) // (block, (ixy, ext))
+	node1, ok := bnode.children[byte('i')]
+	require.True(ok)
+	bnode1, ok := node1.(*branchNode)
+	require.True(ok)
+	require.Len(bnode1.children, 2) // ixy, ext
+	node2, ok := bnode1.children[byte('o')]
+	require.True(ok)
+	enode2, ok := node2.(*extensionNode)
+	require.True(ok)
+	require.Equal([]byte(""), enode2.path)
+	require.Len(enode2.child.(*branchNode).children, 2)
+	checkLeaf(require, bnode1, keyType("ixy"), 1, []byte("dog"))
+
+	// insert wrong key
+	for _, key := range []keyType{
+		keyType("i"), keyType("bloc"), keyType("iote"), keyType("ioabc12345678"),
+	} {
+		require.Panics(func() { node.Upsert(cli, key, 0, []byte("ch")) }, "index out of range in commonPrefixLength.")
+	}
+
+	// check key
+	node1, err = node.Search(cli, keyType("iotex"), 0)
+	require.NoError(err)
+	require.Equal([]byte("chain"), node1.(*leafNode).value)
+	node1, err = node.Search(cli, keyType("ioabc123"), 0)
+	require.NoError(err)
+	require.Equal([]byte("chabc"), node1.(*leafNode).value)
+	node1, err = node.Search(cli, keyType("block"), 0)
+	require.NoError(err)
+	require.Equal([]byte("chain"), node1.(*leafNode).value)
+	node1, err = node.Search(cli, keyType("ixy"), 0)
+	require.NoError(err)
+	require.Equal([]byte("dog"), node1.(*leafNode).value)
+
+	// branch.Delete case2 case *extensionNode -> branch.Delete b.updateChild -> branch
+	node, err = node.Delete(cli, keyType("ixy"), 0)
+	require.NoError(err)
+	bnode, ok = node.(*branchNode)
+	require.True(ok)
+	require.Len(bnode.children, 2) // block, ext
+	checkLeaf(require, bnode, keyType("block"), 0, []byte("chain"))
+	enode, ok = bnode.children[byte('i')].(*extensionNode)
+	require.True(ok)
+	require.Equal([]byte("o"), enode.path)
+	require.Len(enode.child.(*branchNode).children, 2)
+	node1, err = node.Search(cli, keyType("ixy"), 0)
+	require.Equal(trie.ErrNotExist, err)
+
+	// branch.Delete case2 case *extensionNode -> extension
+	node, err = node.Delete(cli, keyType("block"), 0)
+	require.NoError(err)
+	enode, ok = node.(*extensionNode)
+	require.True(ok)
+	require.Equal([]byte("io"), enode.path)
+	require.Len(enode2.child.(*branchNode).children, 2)
+	node1, err = node.Search(cli, keyType("block"), 0)
+	require.Equal(trie.ErrNotExist, err)
+
+	// extension.Delete default -> branch.Delete case2 case *leafNode -> leaf
+	node, err = node.Delete(cli, keyType("iotex"), 0)
+	require.NoError(err)
+	leaf, ok = node.(*leafNode)
+	require.True(ok)
+	require.Equal(keyType("ioabc123"), leaf.key)
+	require.Equal([]byte("chabc"), leaf.value)
+	node1, err = node.Search(cli, keyType("iotex"), 0)
+	require.Equal(trie.ErrNotExist, err)
+
+	// leaf.Delete -> nil
+	node, err = node.Delete(cli, keyType("ioabc123"), 0)
+	require.NoError(err)
+	require.Nil(node)
+
+	// key is nil
+	node, err = newLeafNode(cli, keyType{}, []byte("0"))
+	require.NoError(err)
+	node1, err = node.Search(cli, keyType{}, 0)
+	require.NoError(err)
+	require.Equal([]byte("0"), node1.(*leafNode).value)
+	_, err = node.Delete(cli, keyType("123"), 0)
+	require.Equal(trie.ErrNotExist, err)
+	node2, err = node.Delete(cli, keyType{}, 0)
+	require.NoError(err)
+	require.Nil(node2)
+}