cpp-bignumber/test/biginteger_test.cpp

//
//  biginteger_test.cpp
//  bigdecimal
//
//  Created by Sam Jaffe on 5/18/18.
//

#include "bignumber_test_printers.h"
#include "xcode_gtest_helper.h"

TEST(BigIntegerTest, ModuloZeroThrows) {
  math::biginteger bi{1000};
  EXPECT_THROW(bi % 0, std::domain_error);
}

TEST(BigIntegerTest, ModuloBiggerIsSameValue) {
  math::biginteger bi{1000};
  EXPECT_THAT(bi % 2000, bi);
}

TEST(BigIntegerTest, ModuloSameNumberIsZero) {
  math::biginteger bi{1000};
  EXPECT_THAT(bi % 1000, 0);
}

TEST(BigIntegerTest, ModuloDivisorIsZero) {
  math::biginteger bi{1000};
  EXPECT_THAT(bi % 100, 0);
}

TEST(BigIntegerTest, ModuloDiffSignIsInverseElement) {
  math::biginteger bi{1000};
  math::biginteger mod{13};
  EXPECT_THAT((bi % mod) + ((-bi) % mod), mod);
}

TEST(BigIntegerTest, ModuloNegativesIsNegative) {
  math::biginteger bi{1000};
  math::biginteger mod{13};
  EXPECT_THAT((bi % mod), -((-bi) % (-mod)));
}

class BigIntModuloTest : public testing::TestWithParam<BigIntPair> {};

TEST_P(BigIntModuloTest, IsZero) {
  auto & ZERO = math::biginteger::ZERO;
  auto pair = GetParam();
  EXPECT_THAT(std::get<0>(pair) % std::get<1>(pair), ZERO);
}

class LtTest : public testing::TestWithParam<BigIntPair> {};

TEST_P(LtTest, IsLessThan) {
  auto pair = GetParam();
  EXPECT_THAT(std::get<0>(pair), testing::Lt(std::get<1>(pair)));
}

INSTANTIATE_TEST_SUITE_P(BigInteger, LtTest,
                         testing::Values(BigIntPair{-1, 1}, BigIntPair{0, 1},
                                         BigIntPair{-2, -1},
                                         BigIntPair{1000000000, 1000000001},
                                         BigIntPair{-1000000001, -1000000000}));

INSTANTIATE_TEST_SUITE_P(ZeroModAny, BigIntModuloTest,
                         testing::Combine(testing::Values(0),
                                          testing::Values(1, 2, 10, 100, -4,
                                                          1000000000,
                                                          -1000000000)));

INSTANTIATE_TEST_SUITE_P(AnyModOne, BigIntModuloTest,
                         testing::Combine(testing::Values(1, 2, 10, 100, -4,
                                                          1000000000,
                                                          -1000000000),
                                          testing::Values(1)));