fix(lib/trie): Make sure writing and reading a trie to disk gives the same trie and cover more store/load child trie related test cases

lib/trie/database.go

@@ -209,11 +209,13 @@ func (t *Trie) load(db chaindb.Database, n Node) error {
 	for _, key := range t.GetKeysWithPrefix(ChildStorageKeyPrefix) {
 		childTrie := NewEmptyTrie()
 		value := t.Get(key)
+		// TODO: Tests this error
 		err := childTrie.Load(db, common.NewHash(value))
 		if err != nil {
 			return fmt.Errorf("failed to load child trie with root hash=0x%x: %w", value, err)
 		}
 
+		// TODO: Test this error
 		err = t.PutChild(value, childTrie)
 		if err != nil {
 			return fmt.Errorf("failed to insert child trie with root hash=0x%x into main trie: %w",

lib/trie/database_test.go

@@ -5,11 +5,14 @@ package trie
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
 	"testing"
 
 	"github.com/ChainSafe/chaindb"
+	"github.com/ChainSafe/gossamer/internal/trie/node"
 	"github.com/ChainSafe/gossamer/lib/utils"
+	gomock "github.com/golang/mock/gomock"
 	"github.com/stretchr/testify/require"
 )
 
@@ -387,3 +390,53 @@ func TestTrie_GetFromDB(t *testing.T) {
 		}
 	}
 }
+
+func TestLoadWithChildTriesFails(t *testing.T) {
+	// Use a fake node implementation in which Encode always fails
+	// Make that root of one of the childtries
+	// Run load and check that it fails
+
+	testCase := []Test{
+		{key: []byte{0x01, 0x35}, value: []byte("pen")},
+		{key: []byte{0x01, 0x35, 0x79}, value: []byte("penguin")},
+		{key: []byte{0x01, 0x35, 0x7}, value: []byte("g")},
+		{key: []byte{0xf2}, value: []byte("feather")},
+		{key: []byte{0xf2, 0x3}, value: []byte("f")},
+		{key: []byte{0x09, 0xd3}, value: []byte("noot")},
+		{key: []byte{0x07}, value: []byte("ramen")},
+		{key: []byte{0}, value: nil},
+	}
+
+	trie := NewEmptyTrie()
+
+	for _, test := range testCase {
+		trie.Put(test.key, test.value)
+	}
+	sampleChildTrie := NewEmptyTrie()
+
+	mockCtrl := gomock.NewController(t)
+	defer mockCtrl.Finish()
+	mockNode := node.NewMockNode(mockCtrl)
+	mockNode.EXPECT().Encode(gomock.Any()).AnyTimes().Return(nil)
+	// TODO: Mock remaining methods
+
+	sampleChildTrie.root = mockNode
+
+	keyToChild := []byte("test")
+	err := trie.PutChild(keyToChild, sampleChildTrie)
+	require.NoError(t, err)
+
+	db := newTestDB(t)
+	err = trie.Store(db)
+	require.NoError(t, err)
+
+	mockNode.EXPECT().Encode(gomock.Any()).AnyTimes().Return(errors.New("some error"))
+
+	res := NewEmptyTrie()
+	err = res.Load(db, trie.MustHash())
+	require.NoError(t, err)
+	fmt.Printf("expected:\n %s\n", trie.String())
+	fmt.Printf("actual:\n %s\n", res.String())
+
+	require.Equal(t, trie.MustHash(), res.MustHash())
+}