smst_example_test.go

package smt_test

import (
	"crypto/sha256"
	"testing"

	"github.com/stretchr/testify/require"

	"github.com/pokt-network/smt"
	"github.com/pokt-network/smt/kvstore/simplemap"
)

// TestExampleSMT is a test that aims to act as an example of how to use the SMST.
func TestExampleSMST(t *testing.T) {
	// Initialise a new in-memory key-value store to store the nodes of the trie
	// (Note: the trie only stores hashed values, not raw value data)
	nodeStore := simplemap.NewSimpleMap()

	// Initialise the trie
	trie := smt.NewSparseMerkleSumTrie(nodeStore, sha256.New())

	// Update trie with keys, values and their sums
	_ = trie.Update([]byte("foo"), []byte("oof"), 10)
	_ = trie.Update([]byte("baz"), []byte("zab"), 7)
	_ = trie.Update([]byte("bin"), []byte("nib"), 3)

	// Commit the changes to the nodeStore
	_ = trie.Commit()

	// Calculate the total sum of the trie
	_ = trie.MustSum() // 20

	// Generate a Merkle proof for "foo"
	proof1, _ := trie.Prove([]byte("foo"))
	proof2, _ := trie.Prove([]byte("baz"))
	proof3, _ := trie.Prove([]byte("bin"))

	// We also need the current trie root for the proof
	root := trie.Root()

	// Verify the Merkle proof for "foo"="oof" where "foo" has a sum of 10
	valid_true1, _ := smt.VerifySumProof(proof1, root, []byte("foo"), []byte("oof"), 10, 1, trie.Spec())
	require.True(t, valid_true1)
	// Verify the Merkle proof for "baz"="zab" where "baz" has a sum of 7
	valid_true2, _ := smt.VerifySumProof(proof2, root, []byte("baz"), []byte("zab"), 7, 1, trie.Spec())
	require.True(t, valid_true2)
	// Verify the Merkle proof for "bin"="nib" where "bin" has a sum of 3
	valid_true3, _ := smt.VerifySumProof(proof3, root, []byte("bin"), []byte("nib"), 3, 1, trie.Spec())
	require.True(t, valid_true3)
	// Fail to verify the Merkle proof for "foo"="oof" where "foo" has a sum of 11
	valid_false1, _ := smt.VerifySumProof(proof1, root, []byte("foo"), []byte("oof"), 11, 1, trie.Spec())
	require.False(t, valid_false1)

	// Verify the total sum of the trie
	require.EqualValues(t, 20, trie.MustSum())

	// Verify the number of non-empty leafs in the trie
	require.EqualValues(t, 3, trie.MustCount())
}