Shade/packages/shade-key-transparency/tests/index-tree.test.ts

import { describe, expect, test } from 'bun:test';
import {
  AddressIndex,
  compareAddresses,
  computeIndexRoot,
  emptyRootHash,
  verifyAbsenceProof,
  verifyInclusionProof,
} from '../src/index.js';

describe('AddressIndex', () => {
  test('empty index has emptyRootHash root', () => {
    const idx = new AddressIndex();
    expect(idx.rootHash()).toEqual(emptyRootHash());
  });

  test('upsert keeps entries lexicographically sorted', () => {
    const idx = new AddressIndex();
    idx.upsert({
      address: 'charlie',
      latestLeafIndex: 1,
      bundleHash: new Uint8Array(32).fill(3),
      deleted: false,
    });
    idx.upsert({
      address: 'alice',
      latestLeafIndex: 0,
      bundleHash: new Uint8Array(32).fill(1),
      deleted: false,
    });
    idx.upsert({
      address: 'bob',
      latestLeafIndex: 2,
      bundleHash: new Uint8Array(32).fill(2),
      deleted: false,
    });

    const snap = idx.snapshot();
    expect(snap.map((e) => e.address)).toEqual(['alice', 'bob', 'charlie']);
  });

  test('compareAddresses is byte-lex', () => {
    expect(compareAddresses('alice', 'bob') < 0).toBe(true);
    expect(compareAddresses('bob', 'alice') > 0).toBe(true);
    expect(compareAddresses('alice', 'alice')).toBe(0);
    expect(compareAddresses('alice', 'aliceb')).toBeLessThan(0);
  });

  test('inclusion proof verifies against rootHash', () => {
    const idx = new AddressIndex();
    for (const a of ['alice', 'bob', 'charlie', 'dave', 'eve']) {
      idx.upsert({
        address: a,
        latestLeafIndex: 0,
        bundleHash: new Uint8Array(32).fill(a.charCodeAt(0)),
        deleted: false,
      });
    }
    const proof = idx.inclusionProof('charlie');
    expect(proof).not.toBeNull();
    expect(verifyInclusionProof(proof!, idx.rootHash())).toBe(true);
  });

  test('inclusion proof fails against tampered root', () => {
    const idx = new AddressIndex();
    idx.upsert({
      address: 'alice',
      latestLeafIndex: 0,
      bundleHash: new Uint8Array(32).fill(1),
      deleted: false,
    });
    const proof = idx.inclusionProof('alice')!;
    const tampered = new Uint8Array(idx.rootHash());
    tampered[0] ^= 0xff;
    expect(verifyInclusionProof(proof, tampered)).toBe(false);
  });

  test('absence proof: query between two entries', () => {
    const idx = new AddressIndex();
    idx.upsert({
      address: 'alice',
      latestLeafIndex: 0,
      bundleHash: new Uint8Array(32).fill(1),
      deleted: false,
    });
    idx.upsert({
      address: 'charlie',
      latestLeafIndex: 1,
      bundleHash: new Uint8Array(32).fill(3),
      deleted: false,
    });

    const absence = idx.absenceProof('bob');
    expect(absence).not.toBeNull();
    expect(verifyAbsenceProof(absence!, idx.rootHash())).toBe(true);
  });

  test('absence proof: query before first entry', () => {
    const idx = new AddressIndex();
    idx.upsert({
      address: 'm',
      latestLeafIndex: 0,
      bundleHash: new Uint8Array(32).fill(1),
      deleted: false,
    });
    idx.upsert({
      address: 'z',
      latestLeafIndex: 1,
      bundleHash: new Uint8Array(32).fill(2),
      deleted: false,
    });

    const absence = idx.absenceProof('a');
    expect(absence!.prev).toBeNull();
    expect(absence!.next).not.toBeNull();
    expect(verifyAbsenceProof(absence!, idx.rootHash())).toBe(true);
  });

  test('absence proof: query after last entry', () => {
    const idx = new AddressIndex();
    idx.upsert({
      address: 'a',
      latestLeafIndex: 0,
      bundleHash: new Uint8Array(32).fill(1),
      deleted: false,
    });
    idx.upsert({
      address: 'm',
      latestLeafIndex: 1,
      bundleHash: new Uint8Array(32).fill(2),
      deleted: false,
    });

    const absence = idx.absenceProof('z');
    expect(absence!.prev).not.toBeNull();
    expect(absence!.next).toBeNull();
    expect(verifyAbsenceProof(absence!, idx.rootHash())).toBe(true);
  });

  test('absence proof: empty tree', () => {
    const idx = new AddressIndex();
    const absence = idx.absenceProof('alice');
    expect(absence).not.toBeNull();
    expect(absence!.treeSize).toBe(0);
    expect(verifyAbsenceProof(absence!, idx.rootHash())).toBe(true);
  });

  test('absence proof returns null for existing address', () => {
    const idx = new AddressIndex();
    idx.upsert({
      address: 'alice',
      latestLeafIndex: 0,
      bundleHash: new Uint8Array(32).fill(1),
      deleted: false,
    });
    expect(idx.absenceProof('alice')).toBeNull();
  });

  test('absence proof can be forged-detected: claim adjacent but not adjacent', () => {
    const idx = new AddressIndex();
    idx.upsert({
      address: 'alice',
      latestLeafIndex: 0,
      bundleHash: new Uint8Array(32).fill(1),
      deleted: false,
    });
    idx.upsert({
      address: 'bob',
      latestLeafIndex: 1,
      bundleHash: new Uint8Array(32).fill(2),
      deleted: false,
    });
    idx.upsert({
      address: 'charlie',
      latestLeafIndex: 2,
      bundleHash: new Uint8Array(32).fill(3),
      deleted: false,
    });

    const absence = idx.absenceProof('aaron')!;
    // Tamper: replace prev with non-adjacent neighbor (charlie)
    const charlieProof = idx.inclusionProof('charlie')!;
    const forged = {
      ...absence,
      prev: {
        position: charlieProof.position,
        entry: charlieProof.entry,
        auditPath: charlieProof.auditPath,
      },
    };
    expect(verifyAbsenceProof(forged, idx.rootHash())).toBe(false);
  });

  test('tombstone marks entry deleted', () => {
    const idx = new AddressIndex();
    idx.upsert({
      address: 'alice',
      latestLeafIndex: 0,
      bundleHash: new Uint8Array(32).fill(1),
      deleted: false,
    });
    idx.tombstone('alice', 5);
    const e = idx.get('alice')!;
    expect(e.deleted).toBe(true);
    expect(e.latestLeafIndex).toBe(5);
    expect(e.bundleHash.length).toBe(0);
  });

  test('computeIndexRoot equals AddressIndex.rootHash for the same sorted snapshot', () => {
    const idx = new AddressIndex();
    for (const a of ['carol', 'alice', 'bob']) {
      idx.upsert({
        address: a,
        latestLeafIndex: 0,
        bundleHash: new Uint8Array(32).fill(a.charCodeAt(0)),
        deleted: false,
      });
    }
    expect(idx.rootHash()).toEqual(computeIndexRoot(idx.snapshot()));
  });
});