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#include <boost/test/unit_test.hpp>
#include "stdlib.h"
#include "rpc/blockchain.cpp"
#include "test/test_bitcoin.h"
/* Equality between doubles is imprecise. Comparison should be done
* with a small threshold of tolerance, rather than exact equality.
*/
bool DoubleEquals(double a, double b, double epsilon)
{
return std::abs(a - b) < epsilon;
}
CBlockIndex* CreateBlockIndexWithNbits(uint32_t nbits)
{
CBlockIndex* block_index = new CBlockIndex();
block_index->nHeight = 46367;
block_index->nTime = 1269211443;
block_index->nBits = nbits;
return block_index;
}
CChain CreateChainWithNbits(uint32_t nbits)
{
CBlockIndex* block_index = CreateBlockIndexWithNbits(nbits);
CChain chain;
chain.SetTip(block_index);
return chain;
}
void RejectDifficultyMismatch(double difficulty, double expected_difficulty) {
BOOST_CHECK_MESSAGE(
DoubleEquals(difficulty, expected_difficulty, 0.00001),
"Difficulty was " + std::to_string(difficulty)
+ " but was expected to be " + std::to_string(expected_difficulty));
}
/* Given a BlockIndex with the provided nbits,
* verify that the expected difficulty results.
*/
void TestDifficulty(uint32_t nbits, double expected_difficulty)
{
CBlockIndex* block_index = CreateBlockIndexWithNbits(nbits);
/* Since we are passing in block index explicitly,
* there is no need to set up anything within the chain itself.
*/
CChain chain;
double difficulty = GetDifficulty(chain, block_index);
delete block_index;
RejectDifficultyMismatch(difficulty, expected_difficulty);
}
BOOST_FIXTURE_TEST_SUITE(blockchain_tests, BasicTestingSetup)
BOOST_AUTO_TEST_CASE(get_difficulty_for_very_low_target)
{
TestDifficulty(0x1f111111, 0.000001);
}
BOOST_AUTO_TEST_CASE(get_difficulty_for_low_target)
{
TestDifficulty(0x1ef88f6f, 0.000016);
}
BOOST_AUTO_TEST_CASE(get_difficulty_for_mid_target)
{
TestDifficulty(0x1df88f6f, 0.004023);
}
BOOST_AUTO_TEST_CASE(get_difficulty_for_high_target)
{
TestDifficulty(0x1cf88f6f, 1.029916);
}
BOOST_AUTO_TEST_CASE(get_difficulty_for_very_high_target)
{
TestDifficulty(0x12345678, 5913134931067755359633408.0);
}
// Verify that difficulty is 1.0 for an empty chain.
BOOST_AUTO_TEST_CASE(get_difficulty_for_null_tip)
{
CChain chain;
double difficulty = GetDifficulty(chain, nullptr);
RejectDifficultyMismatch(difficulty, 1.0);
}
/* Verify that if difficulty is based upon the block index
* in the chain, if no block index is explicitly specified.
*/
BOOST_AUTO_TEST_CASE(get_difficulty_for_null_block_index)
{
CChain chain = CreateChainWithNbits(0x1df88f6f);
double difficulty = GetDifficulty(chain, nullptr);
delete chain.Tip();
double expected_difficulty = 0.004023;
RejectDifficultyMismatch(difficulty, expected_difficulty);
}
/* Verify that difficulty is based upon the explicitly specified
* block index rather than being taken from the provided chain,
* when both are present.
*/
BOOST_AUTO_TEST_CASE(get_difficulty_for_block_index_overrides_tip)
{
CChain chain = CreateChainWithNbits(0x1df88f6f);
/* This block index's nbits should be used
* instead of the chain's when calculating difficulty.
*/
CBlockIndex* override_block_index = CreateBlockIndexWithNbits(0x12345678);
double difficulty = GetDifficulty(chain, override_block_index);
delete chain.Tip();
delete override_block_index;
RejectDifficultyMismatch(difficulty, 5913134931067755359633408.0);
}
BOOST_AUTO_TEST_SUITE_END()
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