skiplist_tests.cpp raw
1 // Copyright (c) 2014-present The Bitcoin Core developers
2 // Distributed under the MIT software license, see the accompanying
3 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
4
5 #include <chain.h>
6 #include <test/util/random.h>
7 #include <test/util/setup_common.h>
8
9 #include <algorithm>
10 #include <vector>
11 #include <utility>
12
13 #include <boost/test/unit_test.hpp>
14
15 #define SKIPLIST_LENGTH 300000
16
17 BOOST_FIXTURE_TEST_SUITE(skiplist_tests, BasicTestingSetup)
18
19 BOOST_AUTO_TEST_CASE(skiplist_test)
20 {
21 std::vector<CBlockIndex> vIndex(SKIPLIST_LENGTH);
22
23 for (int i=0; i<SKIPLIST_LENGTH; i++) {
24 vIndex[i].nHeight = i;
25 vIndex[i].pprev = (i == 0) ? nullptr : &vIndex[i - 1];
26 vIndex[i].BuildSkip();
27 }
28
29 for (int i=0; i<SKIPLIST_LENGTH; i++) {
30 if (i > 0) {
31 BOOST_CHECK(vIndex[i].pskip == &vIndex[vIndex[i].pskip->nHeight]);
32 BOOST_CHECK(vIndex[i].pskip->nHeight < i);
33 } else {
34 BOOST_CHECK(vIndex[i].pskip == nullptr);
35 }
36 }
37
38 for (int i=0; i < 1000; i++) {
39 int from = m_rng.randrange(SKIPLIST_LENGTH - 1);
40 int to = m_rng.randrange(from + 1);
41
42 BOOST_CHECK(vIndex[SKIPLIST_LENGTH - 1].GetAncestor(from) == &vIndex[from]);
43 BOOST_CHECK(vIndex[from].GetAncestor(to) == &vIndex[to]);
44 BOOST_CHECK(vIndex[from].GetAncestor(0) == vIndex.data());
45 }
46 }
47
48 BOOST_AUTO_TEST_CASE(getlocator_test)
49 {
50 // Build a main chain 100000 blocks long.
51 std::vector<uint256> vHashMain(100000);
52 std::vector<CBlockIndex> vBlocksMain(100000);
53 for (unsigned int i=0; i<vBlocksMain.size(); i++) {
54 vHashMain[i] = ArithToUint256(i); // Set the hash equal to the height, so we can quickly check the distances.
55 vBlocksMain[i].nHeight = i;
56 vBlocksMain[i].pprev = i ? &vBlocksMain[i - 1] : nullptr;
57 vBlocksMain[i].phashBlock = &vHashMain[i];
58 vBlocksMain[i].BuildSkip();
59 BOOST_CHECK_EQUAL((int)UintToArith256(vBlocksMain[i].GetBlockHash()).GetLow64(), vBlocksMain[i].nHeight);
60 BOOST_CHECK(vBlocksMain[i].pprev == nullptr || vBlocksMain[i].nHeight == vBlocksMain[i].pprev->nHeight + 1);
61 }
62
63 // Build a branch that splits off at block 49999, 50000 blocks long.
64 std::vector<uint256> vHashSide(50000);
65 std::vector<CBlockIndex> vBlocksSide(50000);
66 for (unsigned int i=0; i<vBlocksSide.size(); i++) {
67 vHashSide[i] = ArithToUint256(i + 50000 + (arith_uint256(1) << 128)); // Add 1<<128 to the hashes, so GetLow64() still returns the height.
68 vBlocksSide[i].nHeight = i + 50000;
69 vBlocksSide[i].pprev = i ? &vBlocksSide[i - 1] : (vBlocksMain.data()+49999);
70 vBlocksSide[i].phashBlock = &vHashSide[i];
71 vBlocksSide[i].BuildSkip();
72 BOOST_CHECK_EQUAL((int)UintToArith256(vBlocksSide[i].GetBlockHash()).GetLow64(), vBlocksSide[i].nHeight);
73 BOOST_CHECK(vBlocksSide[i].pprev == nullptr || vBlocksSide[i].nHeight == vBlocksSide[i].pprev->nHeight + 1);
74 }
75
76 // Build a CChain for the main branch.
77 CChain chain;
78 chain.SetTip(vBlocksMain.back());
79
80 // Test 100 random starting points for locators.
81 for (int n=0; n<100; n++) {
82 int r = m_rng.randrange(150000);
83 CBlockIndex* tip = (r < 100000) ? &vBlocksMain[r] : &vBlocksSide[r - 100000];
84 CBlockLocator locator = GetLocator(tip);
85
86 // The first result must be the block itself, the last one must be genesis.
87 BOOST_CHECK(locator.vHave.front() == tip->GetBlockHash());
88 BOOST_CHECK(locator.vHave.back() == vBlocksMain[0].GetBlockHash());
89
90 // Entries 1 through 11 (inclusive) go back one step each.
91 for (unsigned int i = 1; i < 12 && i < locator.vHave.size() - 1; i++) {
92 BOOST_CHECK_EQUAL(UintToArith256(locator.vHave[i]).GetLow64(), tip->nHeight - i);
93 }
94
95 // The further ones (excluding the last one) go back with exponential steps.
96 unsigned int dist = 2;
97 for (unsigned int i = 12; i < locator.vHave.size() - 1; i++) {
98 BOOST_CHECK_EQUAL(UintToArith256(locator.vHave[i - 1]).GetLow64() - UintToArith256(locator.vHave[i]).GetLow64(), dist);
99 dist *= 2;
100 }
101 }
102 }
103
104 BOOST_AUTO_TEST_CASE(findearliestatleast_test)
105 {
106 std::vector<uint256> vHashMain(100000);
107 std::vector<CBlockIndex> vBlocksMain(100000);
108 for (unsigned int i=0; i<vBlocksMain.size(); i++) {
109 vHashMain[i] = ArithToUint256(i); // Set the hash equal to the height
110 vBlocksMain[i].nHeight = i;
111 vBlocksMain[i].pprev = i ? &vBlocksMain[i - 1] : nullptr;
112 vBlocksMain[i].phashBlock = &vHashMain[i];
113 vBlocksMain[i].BuildSkip();
114 if (i < 10) {
115 vBlocksMain[i].nTime = i;
116 vBlocksMain[i].nTimeMax = i;
117 } else {
118 // randomly choose something in the range [MTP, MTP*2]
119 int64_t medianTimePast = vBlocksMain[i].GetMedianTimePast();
120 int r{int(m_rng.randrange(medianTimePast))};
121 vBlocksMain[i].nTime = uint32_t(r + medianTimePast);
122 vBlocksMain[i].nTimeMax = std::max(vBlocksMain[i].nTime, vBlocksMain[i-1].nTimeMax);
123 }
124 }
125 // Check that we set nTimeMax up correctly.
126 unsigned int curTimeMax = 0;
127 for (unsigned int i=0; i<vBlocksMain.size(); ++i) {
128 curTimeMax = std::max(curTimeMax, vBlocksMain[i].nTime);
129 BOOST_CHECK(curTimeMax == vBlocksMain[i].nTimeMax);
130 }
131
132 // Build a CChain for the main branch.
133 CChain chain;
134 chain.SetTip(vBlocksMain.back());
135
136 // Verify that FindEarliestAtLeast is correct.
137 for (unsigned int i=0; i<10000; ++i) {
138 // Pick a random element in vBlocksMain.
139 int r = m_rng.randrange(vBlocksMain.size());
140 int64_t test_time = vBlocksMain[r].nTime;
141 CBlockIndex* ret = chain.FindEarliestAtLeast(test_time, 0);
142 BOOST_CHECK(ret->nTimeMax >= test_time);
143 BOOST_CHECK((ret->pprev==nullptr) || ret->pprev->nTimeMax < test_time);
144 BOOST_CHECK(vBlocksMain[r].GetAncestor(ret->nHeight) == ret);
145 }
146 }
147
148 BOOST_AUTO_TEST_CASE(findearliestatleast_edge_test)
149 {
150 std::list<CBlockIndex> blocks;
151 for (const unsigned int timeMax : {100, 100, 100, 200, 200, 200, 300, 300, 300}) {
152 CBlockIndex* prev = blocks.empty() ? nullptr : &blocks.back();
153 blocks.emplace_back();
154 blocks.back().nHeight = prev ? prev->nHeight + 1 : 0;
155 blocks.back().pprev = prev;
156 blocks.back().BuildSkip();
157 blocks.back().nTimeMax = timeMax;
158 }
159
160 CChain chain;
161 chain.SetTip(blocks.back());
162
163 BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(50, 0)->nHeight, 0);
164 BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(100, 0)->nHeight, 0);
165 BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(150, 0)->nHeight, 3);
166 BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(200, 0)->nHeight, 3);
167 BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(250, 0)->nHeight, 6);
168 BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(300, 0)->nHeight, 6);
169 BOOST_CHECK(!chain.FindEarliestAtLeast(350, 0));
170
171 BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(0, 0)->nHeight, 0);
172 BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(-1, 0)->nHeight, 0);
173
174 BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(std::numeric_limits<int64_t>::min(), 0)->nHeight, 0);
175 BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(-int64_t(std::numeric_limits<unsigned int>::max()) - 1, 0)->nHeight, 0);
176 BOOST_CHECK(!chain.FindEarliestAtLeast(std::numeric_limits<int64_t>::max(), 0));
177 BOOST_CHECK(!chain.FindEarliestAtLeast(std::numeric_limits<unsigned int>::max(), 0));
178 BOOST_CHECK(!chain.FindEarliestAtLeast(int64_t(std::numeric_limits<unsigned int>::max()) + 1, 0));
179
180 BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(0, -1)->nHeight, 0);
181 BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(0, 0)->nHeight, 0);
182 BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(0, 3)->nHeight, 3);
183 BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(0, 8)->nHeight, 8);
184 BOOST_CHECK(!chain.FindEarliestAtLeast(0, 9));
185
186 CBlockIndex* ret1 = chain.FindEarliestAtLeast(100, 2);
187 BOOST_CHECK(ret1->nTimeMax >= 100 && ret1->nHeight == 2);
188 BOOST_CHECK(!chain.FindEarliestAtLeast(300, 9));
189 CBlockIndex* ret2 = chain.FindEarliestAtLeast(200, 4);
190 BOOST_CHECK(ret2->nTimeMax >= 200 && ret2->nHeight == 4);
191 }
192
193 BOOST_AUTO_TEST_CASE(build_skip_height_test)
194 {
195 // clang-format off
196 const std::pair<int, int> TEST_DATA[]{
197 // EVEN values: the rightmost set bit is zeroed
198 // Various even values with at least 2 bits set
199 { 0b00010010 ,
200 0b00010000 },
201 { 0b00100010 ,
202 0b00100000 },
203 { 0b01000010 ,
204 0b01000000 },
205 { 0b00010100 ,
206 0b00010000 },
207 { 0b00011000 ,
208 0b00010000 },
209 { 0b10101010 ,
210 0b10101000 },
211 // ODD values: the 2nd and 3rd set bits are zeroed
212 // Various odd values with at least 4 bits set
213 { 0b10010011 ,
214 0b10000001 },
215 { 0b10100011 ,
216 0b10000001 },
217 { 0b11000011 ,
218 0b10000001 },
219 { 0b10010101 ,
220 0b10000001 },
221 { 0b10011001 ,
222 0b10000001 },
223 { 0b10101011 ,
224 0b10100001 },
225 // Some longer random values (even and odd)
226 { 0b0001011101101000 ,
227 0b0001011101100000 },
228 { 0b0001011101101001 ,
229 0b0001011101000001 },
230 { 0b0110101101011000 ,
231 0b0110101101010000 },
232 { 0b0110101101011001 ,
233 0b0110101101000001 },
234 // All values 1-20
235 { 1, 0 },
236 { 2, 0 },
237 { 3, 1 },
238 { 4, 0 },
239 { 5, 1 },
240 { 6, 4 },
241 { 7, 1 },
242 { 8, 0 },
243 { 9, 1 },
244 { 10, 8 },
245 { 11, 1 },
246 { 12, 8 },
247 { 13, 1 },
248 { 14, 12 },
249 { 15, 9 },
250 { 16, 0 },
251 { 17, 1 },
252 { 18, 16 },
253 { 19, 1 },
254 { 20, 16 },
255 };
256 // clang-format on
257
258 // Test `CBlockIndex::BuildSkip()` and that the skip height conforms to expected logic.
259 // It tests that:
260 // - `pprev` field is set (to an earlier block index),
261 // - the skip is to the index as dictated by the `GetSkipHeight()` bit-manipulation logic,
262 // - `GetAncestor()` works as expected (indirectly).
263
264 // Build a chain (up to the highest test input value)
265 const auto max_test_input{std::ranges::max_element(TEST_DATA, [](auto& a, auto& b) { return a.first < b.first; })};
266 const int chain_size{max_test_input->first + 1};
267 std::vector<CBlockIndex> block_index(chain_size);
268 for (auto i{0}; i < chain_size; ++i) {
269 // pprev and nHeight are used by BuildSkip()
270 block_index[i].pprev = i == 0 ? nullptr : &block_index[i - 1];
271 block_index[i].nHeight = i;
272 block_index[i].BuildSkip();
273 BOOST_CHECK(block_index[i].pskip || i == 0);
274 }
275
276 for (auto& [input, expected] : TEST_DATA) {
277 BOOST_REQUIRE_LT(input, chain_size);
278 BOOST_REQUIRE_GT(input, 0);
279 BOOST_REQUIRE_LT(expected, input);
280 BOOST_REQUIRE(block_index[input].pskip);
281
282 const int skip_height{block_index[input].pskip->nHeight};
283 BOOST_CHECK_EQUAL(skip_height, expected);
284 }
285
286 // Special value: height 0 (genesis) has no skip
287 BOOST_CHECK(!block_index[0].pskip);
288 }
289
290 BOOST_AUTO_TEST_SUITE_END()
291