hex: add tests

Author: pennam

extras/test/CMakeLists.txt

@@ -26,13 +26,14 @@ set(TEST_SRCS
   src/crc32/test_crc32.cpp
   src/crc16/test_crc16.cpp
   src/sha256/test_sha256.cpp
+  src/hex/test_hex.cpp
 )
 
 set(TEST_DUT_SRCS
   ../../src/crc/crc32.cpp
   ../../src/crc/crc16.cpp
-  ../../src/sha256/SHA256.cpp
   ../../src/sha256/sha2.c
+  ../../src/hex/chex.h
 )
 
 ##########################################################################

extras/test/src/hex/test_hex.cpp

@@ -0,0 +1,53 @@
+/*
+    This file is part of the Arduino_CloudUtils library.
+
+    Copyright (c) 2024 Arduino SA
+
+    This Source Code Form is subject to the terms of the Mozilla Public
+    License, v. 2.0. If a copy of the MPL was not distributed with this
+    file, You can obtain one at http://mozilla.org/MPL/2.0/.
+*/
+
+#include <catch2/catch_test_macros.hpp>
+
+#include <hex/chex.h>
+
+SCENARIO( "HEX encoding test" ) {
+    /* check all possible 16-bit values in network byte order */
+    unsigned i;
+    for(i = 0; i <= 0xffff; ++i){
+        /* encode to hex string using our implementation */
+        const unsigned char org[2] = {(unsigned char)(i>>8), (unsigned char)i};
+        char hex[5];
+        chex_encode(hex, sizeof(hex), org, sizeof(org));
+
+        /* decode from hex string using a function from the standard library */
+        unsigned char bin[2];
+        int n = sscanf(hex, "%02hhx%02hhx", bin, bin+1);
+        REQUIRE(n == sizeof(bin));
+
+        /* decoded matches the original */
+        REQUIRE(memcmp(org, bin, sizeof(bin)) == 0);
+    }
+    REQUIRE(i == 0x10000);
+}
+
+SCENARIO( "HEX decoding test" ) {
+    /* check all possible 16-bit values in network byte order */
+    unsigned i;
+    for(i = 0; i <= 0xffff; ++i){
+        /* encode to hex string using a function from the standard library */
+        char hex[5];
+        snprintf(hex, sizeof(hex), "%02hhX%02hhx", (unsigned char)(i>>8), (unsigned char)i);
+
+        /* decode from hex string using our implementation */
+        unsigned char bin[2];
+        unsigned n = chex_decode(bin, sizeof(bin), hex, sizeof(hex));
+        REQUIRE(n == sizeof(bin));
+
+        /* decoded matches the original */
+        const unsigned char org[2] = {(unsigned char)(i>>8), (unsigned char)i};
+        REQUIRE(memcmp(org, bin, sizeof(bin)) == 0);
+    }
+    REQUIRE(i == 0x10000);
+}