tests/echo/tests_for_hextobin.c

#include "../../unity/unity.h"
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <limits.h>

/* Unity required hooks */
void setUp(void) {
  /* No setup needed */
}
void tearDown(void) {
  /* No teardown needed */
}

/* Tests for static int hextobin(unsigned char c) */

void test_hextobin_digits_0_through_9(void) {
  for (int ic = '0'; ic <= '9'; ic++) {
    unsigned char c = (unsigned char) ic;
    int got = hextobin(c);
    int expected = ic - '0';
    TEST_ASSERT_EQUAL_INT(expected, got);
  }
}

void test_hextobin_lowercase_a_through_f(void) {
  for (int ic = 'a'; ic <= 'f'; ic++) {
    unsigned char c = (unsigned char) ic;
    int got = hextobin(c);
    int expected = 10 + (ic - 'a');
    TEST_ASSERT_EQUAL_INT(expected, got);
  }
}

void test_hextobin_uppercase_A_through_F(void) {
  for (int ic = 'A'; ic <= 'F'; ic++) {
    unsigned char c = (unsigned char) ic;
    int got = hextobin(c);
    int expected = 10 + (ic - 'A');
    TEST_ASSERT_EQUAL_INT(expected, got);
  }
}

void test_hextobin_non_hex_characters_return_c_minus_zero(void) {
  /* Characters that are not hex digits should fall through to default: c - '0' */
  const unsigned char samples[] = {
    (unsigned char) '/',  /* 47 -> 47 - '0' (likely -1 in ASCII) */
    (unsigned char) 'g',  /* -> 'g' - '0' */
    (unsigned char) 'G',  /* -> 'G' - '0' */
    (unsigned char) ' ',  /* space -> ' ' - '0' (likely negative) */
    (unsigned char) ':',  /* 58 -> ':' - '0' = 10 in ASCII (just above '9') */
    (unsigned char) '\n'  /* newline */
  };
  size_t n = sizeof(samples)/sizeof(samples[0]);
  for (size_t i = 0; i < n; i++) {
    unsigned char c = samples[i];
    int got = hextobin(c);
    int expected = (int)c - '0';
    TEST_ASSERT_EQUAL_INT(expected, got);
  }
}

void test_hextobin_boundary_like_values(void) {
  /* NUL character */
  {
    unsigned char c = (unsigned char) '\0';
    int got = hextobin(c);
    int expected = (int)c - '0';
    TEST_ASSERT_EQUAL_INT(expected, got);
  }
  /* 0xFF (255) as unsigned char */
  {
    unsigned char c = (unsigned char) 0xFF;
    int got = hextobin(c);
    int expected = (int)c - '0';
    TEST_ASSERT_EQUAL_INT(expected, got);
  }
  /* Check exact edges for hex letters */
  {
    unsigned char c1 = (unsigned char) 'a';
    unsigned char c2 = (unsigned char) 'f';
    unsigned char c3 = (unsigned char) 'A';
    unsigned char c4 = (unsigned char) 'F';
    TEST_ASSERT_EQUAL_INT(10, hextobin(c1));
    TEST_ASSERT_EQUAL_INT(15, hextobin(c2));
    TEST_ASSERT_EQUAL_INT(10, hextobin(c3));
    TEST_ASSERT_EQUAL_INT(15, hextobin(c4));
  }
}

/* Unity test runner */
int main(void) {
  UNITY_BEGIN();
  RUN_TEST(test_hextobin_digits_0_through_9);
  RUN_TEST(test_hextobin_lowercase_a_through_f);
  RUN_TEST(test_hextobin_uppercase_A_through_F);
  RUN_TEST(test_hextobin_non_hex_characters_return_c_minus_zero);
  RUN_TEST(test_hextobin_boundary_like_values);
  return UNITY_END();
}