Adding minimal set-up to execute unit tests on this repository.

.github/workflows/unit-tests.yml

@@ -0,0 +1,41 @@
+name: Unit Tests
+
+on:
+  pull_request:
+    paths:
+      - ".github/workflows/unit-tests.yml"
+      - 'extras/test/**'
+      - 'src/**'
+
+  push:
+    paths:
+      - ".github/workflows/unit-tests.yml"
+      - 'extras/test/**'
+      - 'src/**'
+
+jobs:
+  test:
+    name: Run unit tests
+    runs-on: ubuntu-latest
+
+    env:
+      COVERAGE_DATA_PATH: extras/coverage-data/coverage.info
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - uses: arduino/cpp-test-action@main
+        with:
+          runtime-paths: |
+            - extras/test/build/bin/test_cyphal++
+          coverage-exclude-paths: |
+            - '*/extras/test/*'
+            - '/usr/*'
+          coverage-data-path: ${{ env.COVERAGE_DATA_PATH }}
+
+      - name: Upload coverage report to Codecov
+        uses: codecov/codecov-action@v1
+        with:
+          file: "${{ env.COVERAGE_DATA_PATH }}"
+          fail_ci_if_error: true

README.md

@@ -5,6 +5,8 @@
 [![Arduino Library Badge](https://www.ardu-badge.com/badge/107-Arduino-Cyphal.svg?)](https://www.ardu-badge.com/107-Arduino-Cyphal)
 [![Compile Examples](https://github.com/107-systems/107-Arduino-Cyphal/workflows/Compile%20Examples/badge.svg)](https://github.com/107-systems/107-Arduino-Cyphal/actions?workflow=Compile+Examples)
 [![Smoke test status](https://github.com/107-systems/107-Arduino-Cyphal/actions/workflows/smoke-test.yml/badge.svg)](https://github.com/107-systems/107-Arduino-Cyphal/actions/workflows/smoke-test.yml)
+[![Unit Tests](https://github.com/107-systems/107-Arduino-Cyphal/workflows/Unit%20Tests/badge.svg)](https://github.com/107-systems/107-Arduino-Cyphal/actions?workflow=Unit+Tests)
+[![Code Coverage](https://codecov.io/gh/107-systems/107-Arduino-Cyphal/branch/main/graph/badge.svg)](https://codecov.io/gh/107-systems/107-Arduino-Cyphal)
 [![Arduino Lint](https://github.com/107-systems/107-Arduino-Cyphal/workflows/Arduino%20Lint/badge.svg)](https://github.com/107-systems/107-Arduino-Cyphal/actions?workflow=Arduino+Lint)
 [![keywords.txt Checks](https://github.com/107-systems/107-Arduino-Cyphal/workflows/Extra%20Library%20Checks/badge.svg)](https://github.com/107-systems/107-Arduino-Cyphal/actions?workflow=Extra+Library+Checks)
 [![General Formatting Checks](https://github.com/107-systems/107-Arduino-Cyphal/workflows/General%20Formatting%20Checks/badge.svg)](https://github.com/107-systems/107-Arduino-Cyphal/actions?workflow=General+Formatting+Checks)

extras/test/CMakeLists.txt

@@ -0,0 +1,19 @@
+##########################################################################
+cmake_minimum_required(VERSION 3.15)
+##########################################################################
+project("test_cyphal++")
+##########################################################################
+include_directories(external/catch2/v2.13.10/include)
+include_directories(../../src)
+##########################################################################
+set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
+##########################################################################
+set(TEST_TARGET ${CMAKE_PROJECT_NAME})
+##########################################################################
+add_compile_options(-Wall -Wextra -Wpedantic -Werror)
+##########################################################################
+add_executable(${TEST_TARGET}
+  src/test_main.cpp
+  src/test_demo.cpp
+)
+##########################################################################