tests/numfmt/tests_for_simple_round.c

#include "../../unity/unity.h"
#include <limits.h>
#include <stdint.h>
#include <stdio.h>

/* Unity fixtures */
void setUp(void) {
  /* no setup needed */
}
void tearDown(void) {
  /* no teardown needed */
}

/* Helper to assert long double equality for integer results */
static void assert_ld_equal(long double expected, long double actual, const char* msg)
{
  if (!(expected == actual)) {
    char buf[256];
    /* Print with no fractional digits as results are integral */
    snprintf(buf, sizeof(buf), "%s: expected %.0Lf got %.0Lf", msg, expected, actual);
    TEST_FAIL_MESSAGE(buf);
  }
}

/* Convenience: get INTMAX_MAX as long double */
static long double LDMAX(void) {
  return (long double)INTMAX_MAX;
}

/* Basic rounding tests for small values */
void test_simple_round_ceiling_basic(void) {
  TEST_ASSERT_EQUAL_INT(2, (int)simple_round(1.1L, round_ceiling));
  TEST_ASSERT_EQUAL_INT(1, (int)simple_round(1.0L, round_ceiling));
  TEST_ASSERT_EQUAL_INT(-1, (int)simple_round(-1.1L, round_ceiling));
  TEST_ASSERT_EQUAL_INT(-1, (int)simple_round(-1.0L, round_ceiling));
}

void test_simple_round_floor_basic(void) {
  TEST_ASSERT_EQUAL_INT(1, (int)simple_round(1.9L, round_floor));
  TEST_ASSERT_EQUAL_INT(1, (int)simple_round(1.0L, round_floor));
  TEST_ASSERT_EQUAL_INT(-2, (int)simple_round(-1.1L, round_floor));
  TEST_ASSERT_EQUAL_INT(-1, (int)simple_round(-1.0L, round_floor));
}

void test_simple_round_from_zero_basic(void) {
  TEST_ASSERT_EQUAL_INT(2, (int)simple_round(1.1L, round_from_zero));
  TEST_ASSERT_EQUAL_INT(-2, (int)simple_round(-1.1L, round_from_zero));
  TEST_ASSERT_EQUAL_INT(1, (int)simple_round(1.0L, round_from_zero));
  TEST_ASSERT_EQUAL_INT(-1, (int)simple_round(-1.0L, round_from_zero));
}

void test_simple_round_to_zero_basic(void) {
  TEST_ASSERT_EQUAL_INT(1, (int)simple_round(1.9L, round_to_zero));
  TEST_ASSERT_EQUAL_INT(-1, (int)simple_round(-1.9L, round_to_zero));
  TEST_ASSERT_EQUAL_INT(1, (int)simple_round(1.0L, round_to_zero));
  TEST_ASSERT_EQUAL_INT(-1, (int)simple_round(-1.0L, round_to_zero));
}

void test_simple_round_nearest_basic(void) {
  TEST_ASSERT_EQUAL_INT(1, (int)simple_round(1.49L, round_nearest));
  TEST_ASSERT_EQUAL_INT(2, (int)simple_round(1.5L, round_nearest));
  TEST_ASSERT_EQUAL_INT(-1, (int)simple_round(-1.49L, round_nearest));
  TEST_ASSERT_EQUAL_INT(-2, (int)simple_round(-1.5L, round_nearest));
}

/* Boundary behavior around INTMAX_MAX using 0.5 which is representable */
void test_simple_round_near_INTMAX_MAX_ceil_floor(void) {
  long double M = LDMAX();

  /* M - 0.5 */
  long double v1 = M - 0.5L;
  long double ceil_v1 = simple_round(v1, round_ceiling);
  long double floor_v1 = simple_round(v1, round_floor);
  assert_ld_equal(M,          ceil_v1,  "ceil(M-0.5)");
  assert_ld_equal(M - 1.0L,   floor_v1, "floor(M-0.5)");

  /* M + 0.5 */
  long double v2 = M + 0.5L;
  long double ceil_v2 = simple_round(v2, round_ceiling);
  long double floor_v2 = simple_round(v2, round_floor);
  assert_ld_equal(M + 1.0L,   ceil_v2,  "ceil(M+0.5)");
  assert_ld_equal(M,          floor_v2, "floor(M+0.5)");
}

void test_simple_round_near_INTMAX_MAX_from_to_zero(void) {
  long double M = LDMAX();

  /* Positive side */
  long double vp = M + 0.5L;
  assert_ld_equal(M + 1.0L, simple_round(vp, round_from_zero), "from_zero(M+0.5)");
  assert_ld_equal(M,        simple_round(vp, round_to_zero),   "to_zero(M+0.5)");

  /* Negative side */
  long double vn = -(M + 0.5L);
  assert_ld_equal(-(M + 1.0L), simple_round(vn, round_from_zero), "from_zero(-(M+0.5))");
  assert_ld_equal(-M,          simple_round(vn, round_to_zero),   "to_zero(-(M+0.5))");
}

void test_simple_round_near_INTMAX_MAX_nearest(void) {
  long double M = LDMAX();

  /* .5 ties away from zero */
  assert_ld_equal(M + 1.0L, simple_round(M + 0.5L, round_nearest),  "nearest(M+0.5)");
  assert_ld_equal(- (M + 1.0L), simple_round(- (M + 0.5L), round_nearest), "nearest(-(M+0.5))");

  /* Below half goes to nearest integer */
  assert_ld_equal(M,          simple_round(M + 0.49L, round_nearest),  "nearest(M+0.49)");
  assert_ld_equal(-M,         simple_round(- (M + 0.49L), round_nearest), "nearest(-(M+0.49))");
}

/* Large values exercising partitioning logic with multiples of INTMAX_MAX */
void test_simple_round_large_exact_multiples(void) {
  long double M = LDMAX();

  /* Exactly 2*M */
  long double v = 2.0L * M;
  assert_ld_equal(2.0L * M, simple_round(v, round_ceiling),   "ceil(2*M)");
  assert_ld_equal(2.0L * M, simple_round(v, round_floor),     "floor(2*M)");
  assert_ld_equal(2.0L * M, simple_round(v, round_from_zero), "from_zero(2*M)");
  assert_ld_equal(2.0L * M, simple_round(v, round_to_zero),   "to_zero(2*M)");
  assert_ld_equal(2.0L * M, simple_round(v, round_nearest),   "nearest(2*M)");

  /* 2*M + 1 (still an integer) */
  long double v2 = 2.0L * M + 1.0L;
  assert_ld_equal(2.0L * M + 1.0L, simple_round(v2, round_ceiling),   "ceil(2*M+1)");
  assert_ld_equal(2.0L * M + 1.0L, simple_round(v2, round_floor),     "floor(2*M+1)");
  assert_ld_equal(2.0L * M + 1.0L, simple_round(v2, round_from_zero), "from_zero(2*M+1)");
  assert_ld_equal(2.0L * M + 1.0L, simple_round(v2, round_to_zero),   "to_zero(2*M+1)");
  assert_ld_equal(2.0L * M + 1.0L, simple_round(v2, round_nearest),   "nearest(2*M+1)");

  /* Negative exact large values */
  long double vn = - (2.0L * M);
  assert_ld_equal(- (2.0L * M), simple_round(vn, round_ceiling),   "ceil(-2*M)");
  assert_ld_equal(- (2.0L * M), simple_round(vn, round_floor),     "floor(-2*M)");
  assert_ld_equal(- (2.0L * M), simple_round(vn, round_from_zero), "from_zero(-2*M)");
  assert_ld_equal(- (2.0L * M), simple_round(vn, round_to_zero),   "to_zero(-2*M)");
  assert_ld_equal(- (2.0L * M), simple_round(vn, round_nearest),   "nearest(-2*M)");
}

/* Zero edge cases */
void test_simple_round_zero_cases(void) {
  TEST_ASSERT_EQUAL_INT(0, (int)simple_round(0.0L, round_ceiling));
  TEST_ASSERT_EQUAL_INT(0, (int)simple_round(0.0L, round_floor));
  TEST_ASSERT_EQUAL_INT(0, (int)simple_round(0.0L, round_from_zero));
  TEST_ASSERT_EQUAL_INT(0, (int)simple_round(0.0L, round_to_zero));
  TEST_ASSERT_EQUAL_INT(0, (int)simple_round(0.0L, round_nearest));
}

int main(void) {
  UNITY_BEGIN();

  RUN_TEST(test_simple_round_ceiling_basic);
  RUN_TEST(test_simple_round_floor_basic);
  RUN_TEST(test_simple_round_from_zero_basic);
  RUN_TEST(test_simple_round_to_zero_basic);
  RUN_TEST(test_simple_round_nearest_basic);

  RUN_TEST(test_simple_round_near_INTMAX_MAX_ceil_floor);
  RUN_TEST(test_simple_round_near_INTMAX_MAX_from_to_zero);
  RUN_TEST(test_simple_round_near_INTMAX_MAX_nearest);

  RUN_TEST(test_simple_round_large_exact_multiples);
  RUN_TEST(test_simple_round_zero_cases);

  return UNITY_END();
}