tests: rename remaining C unit tests to .cpp (no content changes)

tests/test_base64_cpp.cpp

@@ -0,0 +1,116 @@
+#include <assert.h>
+#include <string.h>
+#include <stdint.h>
+
+#include "base64.h"
+
+static void
+test_encode_decode(void)
+{
+    /* Known test vector: "Hello" */
+    const uint8_t input[] = "Hello";
+    char encoded[BASE64_SIZE(5)];
+    uint8_t decoded[5];
+
+    char *ret = base64_encode(encoded, sizeof(encoded), input, 5);
+    assert(ret != NULL);
+    assert(strlen(encoded) > 0);
+
+    int decoded_len = base64_decode(decoded, encoded, sizeof(decoded));
+    assert(decoded_len == 5);
+    assert(memcmp(decoded, input, 5) == 0);
+}
+
+static void
+test_empty_input(void)
+{
+    char encoded[BASE64_SIZE(0)];
+    char *ret = base64_encode(encoded, sizeof(encoded), (const uint8_t *)"", 0);
+    assert(ret != NULL);
+    assert(strlen(encoded) == 0);
+}
+
+static void
+test_single_byte(void)
+{
+    const uint8_t input[] = { 0x41 }; /* 'A' */
+    char encoded[BASE64_SIZE(1)];
+    uint8_t decoded[1];
+
+    char *ret = base64_encode(encoded, sizeof(encoded), input, 1);
+    assert(ret != NULL);
+
+    int decoded_len = base64_decode(decoded, encoded, sizeof(decoded));
+    assert(decoded_len == 1);
+    assert(decoded[0] == 0x41);
+}
+
+static void
+test_two_bytes(void)
+{
+    const uint8_t input[] = { 0x41, 0x42 }; /* "AB" */
+    char encoded[BASE64_SIZE(2)];
+    uint8_t decoded[2];
+
+    char *ret = base64_encode(encoded, sizeof(encoded), input, 2);
+    assert(ret != NULL);
+
+    int decoded_len = base64_decode(decoded, encoded, sizeof(decoded));
+    assert(decoded_len == 2);
+    assert(decoded[0] == 0x41);
+    assert(decoded[1] == 0x42);
+}
+
+static void
+test_three_bytes(void)
+{
+    const uint8_t input[] = { 0x00, 0xFF, 0x80 };
+    char encoded[BASE64_SIZE(3)];
+    uint8_t decoded[3];
+
+    char *ret = base64_encode(encoded, sizeof(encoded), input, 3);
+    assert(ret != NULL);
+
+    int decoded_len = base64_decode(decoded, encoded, sizeof(decoded));
+    assert(decoded_len == 3);
+    assert(decoded[0] == 0x00);
+    assert(decoded[1] == 0xFF);
+    assert(decoded[2] == 0x80);
+}
+
+static void
+test_roundtrip_binary(void)
+{
+    const uint8_t input[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
+                              10, 11, 12, 13, 14, 15, 16 };
+    char encoded[BASE64_SIZE(17)];
+    uint8_t decoded[17];
+
+    char *ret = base64_encode(encoded, sizeof(encoded), input, 17);
+    assert(ret != NULL);
+
+    int decoded_len = base64_decode(decoded, encoded, sizeof(decoded));
+    assert(decoded_len == 17);
+    assert(memcmp(decoded, input, 17) == 0);
+}
+
+static void
+test_invalid_chars(void)
+{
+    /* Character '!' (ASCII 33) is below the base64 range start ('+' = 43) */
+    int decoded_len = base64_decode((uint8_t[4]){}, "!!!!", 4);
+    assert(decoded_len == -1);
+}
+
+int
+main(void)
+{
+    test_encode_decode();
+    test_empty_input();
+    test_single_byte();
+    test_two_bytes();
+    test_three_bytes();
+    test_roundtrip_binary();
+    test_invalid_chars();
+    return 0;
+}