Add unit tests for Utils::toHex

Author: mtlynch

.github/workflows/run-unit-tests.yml

@@ -0,0 +1,31 @@
+name: Run Unit Tests
+
+on:
+  push:
+    branches:
+      - main
+      - master
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+
+      - name: Clone Repo
+        uses: actions/checkout@v4
+
+      - name: Setup Build Environment
+        uses: ./.github/actions/setup-build-environment
+
+      - name: Run Unit Tests
+        run: pio test -e native -vv
+
+      - name: Upload Test Results
+        # Upload test results even if the test step failed.
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: test-results
+          path: .pio/build/native/

README.md

@@ -93,6 +93,14 @@ Here are some general principals you should try to adhere to:
 * No dynamic memory allocation, except during setup/begin functions.
 * Use the same brace and indenting style that's in the core source modules. (A .clang-format is prob going to be added soon, but please do NOT retroactively re-format existing code. This just creates unnecessary diffs that make finding problems harder)
 
+### Running unit tests
+
+To run unit tests, run the following command:
+
+```bash
+pio test --environment native --verbose
+```
+
 ## Road-Map / To-Do
 
 There are a number of fairly major features in the pipeline, with no particular time-frames attached yet. In very rough chronological order:

platformio.ini

@@ -138,3 +138,17 @@ lib_deps =
   adafruit/Adafruit MLX90614 Library @ ^2.1.5
   adafruit/Adafruit_VL53L0X @ ^1.2.4
   stevemarple/MicroNMEA @ ^2.0.6
+
+; ----------------- TESTING ---------------------
+
+[env:native]
+platform = native
+build_flags = -std=c++14
+  -I src
+  -I test/mocks
+test_build_src = yes
+build_src_filter =
+  -<*>
+  +<../src/Utils.cpp>
+lib_deps =
+  google/googletest @ ^1.15.2

test/mocks/AES.h

@@ -0,0 +1,13 @@
+#pragma once
+
+#include <stdint.h>
+#include <stddef.h>
+
+// Mock AES128 class for testing
+// Provides minimal interface to allow Utils.cpp to compile
+class AES128 {
+public:
+  void setKey(const uint8_t* key, size_t keySize) {}
+  void encryptBlock(uint8_t* output, const uint8_t* input) {}
+  void decryptBlock(uint8_t* output, const uint8_t* input) {}
+};

test/mocks/SHA256.h

@@ -0,0 +1,14 @@
+#pragma once
+
+#include <stdint.h>
+#include <stddef.h>
+
+// Mock SHA256 class for testing
+// Provides minimal interface to allow Utils.cpp to compile
+class SHA256 {
+public:
+  void update(const uint8_t* data, size_t len) {}
+  void finalize(uint8_t* hash, size_t hashLen) {}
+  void resetHMAC(const uint8_t* key, size_t keyLen) {}
+  void finalizeHMAC(const uint8_t* key, size_t keyLen, uint8_t* hash, size_t hashLen) {}
+};

test/mocks/Stream.h

@@ -0,0 +1,10 @@
+#pragma once
+
+// Mock Stream class for native testing
+// Provides minimal interface needed by Utils.h
+
+class Stream {
+public:
+    virtual void print(char c) {}
+    virtual void print(const char* str) {}
+};

test/test_utils/test_tohex.cpp

@@ -0,0 +1,57 @@
+#include <gtest/gtest.h>
+#include "Utils.h"
+
+using namespace mesh;
+
+#define HEX_BUFFER_SIZE(input) (sizeof(input) * 2 + 1)
+
+TEST(UtilsToHex, ConvertSingleByte) {
+    uint8_t input[] = {0xAB};
+    char output[HEX_BUFFER_SIZE(input)];
+
+    Utils::toHex(output, input, sizeof(input));
+
+    EXPECT_STREQ("AB", output);
+}
+
+TEST(UtilsToHex, ConvertMultipleBytes) {
+    uint8_t input[] = {0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF};
+    char output[HEX_BUFFER_SIZE(input)];
+
+    Utils::toHex(output, input, sizeof(input));
+
+    EXPECT_STREQ("0123456789ABCDEF", output);
+}
+
+TEST(UtilsToHex, ConvertZeroByte) {
+    uint8_t input[] = {0x00};
+    char output[HEX_BUFFER_SIZE(input)];
+
+    Utils::toHex(output, input, sizeof(input));
+
+    EXPECT_STREQ("00", output);
+}
+
+TEST(UtilsToHex, ConvertMaxByte) {
+    uint8_t input[] = {0xFF};
+    char output[HEX_BUFFER_SIZE(input)];
+
+    Utils::toHex(output, input, sizeof(input));
+
+    EXPECT_STREQ("FF", output);
+}
+
+TEST(UtilsToHex, NullTerminatesOnEmptyInput) {
+    uint8_t input[] = {0xAB};
+    char output[] = "X";  // Pre-fill with X.
+
+    Utils::toHex(output, input, 0);
+
+    // Should just null-terminate at position 0
+    EXPECT_EQ('\0', output[0]);
+}
+
+int main(int argc, char **argv) {
+    ::testing::InitGoogleTest(&argc, argv);
+    return RUN_ALL_TESTS();
+}