Testing and CI

How the driver is checked: host unit tests against a model of the chip, compiled documentation, ESP32 builds and static analysis, on every pull request.

Host unit tests

The tests build the real driver against a model of the PCA9685's register interface: power-up register values, PRE_SCALE ignoring writes while the chip is awake, the register pointer advancing only with MODE1.AI set, the RESTART bit and the 500 µs oscillator start-up on a model bus clock, and injected I2C failures. Every transaction the driver sends is logged, so tests check the exact bytes and registers.

cmake -S . -B build-host -DHF_PCA9685_BUILD_TESTS=ON
cmake --build build-host
ctest --test-dir build-host --output-on-failure

File	Covers
tests/test_driver.cpp	Initialisation, retries, frequency and prescaler, channel frames, range checks, sleep, MODE2
tests/mock_pca9685.hpp	The register model and transaction log
tests/test_harness.hpp	A dependency-free test registry and CHECK macros
tests/check_install.cmake	CTest hf_pca9685_install: installs into a scratch prefix and builds tests/install_consumer/ with find_package(hf_pca9685)

Documentation snippets

Every C++ block on this site is included from tests/docs/, which the host build compiles (target hf_pca9685_doc_snippets) with the driver instantiated over the documented port. A change to the API that breaks a page breaks the build first.

CI workflows

Workflow	What it checks
Host unit tests	GCC and Clang build and run the tests and the doc snippets
ESP32 examples build	Every app in examples/esp32/app_config.yml, for each listed ESP-IDF version and build type
C++ lint, C++ analysis	clang-format, clang-tidy and cppcheck
Docs	Strict site build, figure and generated-table drift, Doxygen, link check, Lighthouse budget
Markdown lint, YAML lint, link check	Repository text files

The workflows call the shared, versioned workflows of hf-general-ci-tools and hf-espidf-ci-tools.

On hardware

The ESP32 examples are the hardware test suite: pca9685_comprehensive_test prints a pass / fail summary over the serial monitor. Check the outputs with a scope or logic analyser; the test cannot see them.