tests/basenc/tests_for_base2lsbf_encode.c

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

void setUp(void) {
    /* Setup code here, or leave empty */
}

void tearDown(void) {
    /* Cleanup code here, or leave empty */
}

/* Helper: encode single byte and return a null-terminated string in out[9]. */
static void encode_byte(uint8_t byte, char out[9]) {
    char in = (char)byte;
    /* base2lsbf_encode writes exactly 8 chars for one input byte when outlen>=8 */
    base2lsbf_encode(&in, 1, out, 8);
    out[8] = '\0';
}

/* Helper: reconstruct byte value from LSB-first bit string of length 8. */
static uint8_t bits_to_byte(const char bits[8]) {
    uint8_t v = 0;
    for (int i = 0; i < 8; i++) {
        if (bits[i] == '1') v |= (uint8_t)(1u << i);
    }
    return v;
}

static void expect_bits_for_byte(uint8_t b, const char *expected) {
    char out[9];
    encode_byte(b, out);
    TEST_ASSERT_EQUAL_STRING(expected, out);
}

void test_base2lsbf_encode_zero_length_input(void) {
    /* Ensure no writes occur for inlen==0 */
    char outbuf[16];
    memset(outbuf, 'X', sizeof(outbuf));

    /* Call with inlen=0; outlen can be any value, function should not write */
    base2lsbf_encode((const char *)"", 0, outbuf, 16);

    for (size_t i = 0; i < sizeof(outbuf); i++) {
        TEST_ASSERT_EQUAL_CHAR('X', outbuf[i]);
    }
}

void test_base2lsbf_encode_00_all_zeros(void) {
    expect_bits_for_byte(0x00u, "00000000");
}

void test_base2lsbf_encode_ff_all_ones(void) {
    expect_bits_for_byte(0xFFu, "11111111");
}

void test_base2lsbf_encode_01_and_80_edges(void) {
    expect_bits_for_byte(0x01u, "10000000");
    expect_bits_for_byte(0x80u, "00000001");
}

void test_base2lsbf_encode_f0_and_0f_nibbles(void) {
    expect_bits_for_byte(0xF0u, "00001111");
    expect_bits_for_byte(0x0Fu, "11110000");
}

void test_base2lsbf_encode_55_and_aa_patterns(void) {
    expect_bits_for_byte(0x55u, "10101010"); /* 01010101 msb->lsb */
    expect_bits_for_byte(0xAAu, "01010101"); /* 10101010 msb->lsb */
}

void test_base2lsbf_encode_multi_byte_concatenation(void) {
    const unsigned char in[2] = { 0xABu, 0xCDu }; /* 0xAB=10101011, 0xCD=11001101 */
    char out[16];
    /* Expect: 0xAB -> 11010101, 0xCD -> 10110011 */
    const char expected[16] = {
        '1','1','0','1','0','1','0','1',
        '1','0','1','1','0','0','1','1'
    };

    base2lsbf_encode((const char *)in, 2, out, 16);
    TEST_ASSERT_EQUAL_MEMORY(expected, out, 16);
}

void test_base2lsbf_encode_all_byte_values_roundtrip_property(void) {
    char out[9];
    for (int b = 0; b <= 255; b++) {
        encode_byte((uint8_t)b, out);
        uint8_t reconstructed = bits_to_byte(out);
        if (reconstructed != (uint8_t)b) {
            /* Provide diagnostic */
            char msg[128];
            snprintf(msg, sizeof msg, "Mismatch for 0x%02X: got '%s' -> 0x%02X", b, out, reconstructed);
            TEST_FAIL_MESSAGE(msg);
        }
    }
}

int main(void) {
    UNITY_BEGIN();
    RUN_TEST(test_base2lsbf_encode_zero_length_input);
    RUN_TEST(test_base2lsbf_encode_00_all_zeros);
    RUN_TEST(test_base2lsbf_encode_ff_all_ones);
    RUN_TEST(test_base2lsbf_encode_01_and_80_edges);
    RUN_TEST(test_base2lsbf_encode_f0_and_0f_nibbles);
    RUN_TEST(test_base2lsbf_encode_55_and_aa_patterns);
    RUN_TEST(test_base2lsbf_encode_multi_byte_concatenation);
    RUN_TEST(test_base2lsbf_encode_all_byte_values_roundtrip_property);
    return UNITY_END();
}