Pigweed Kernel Testing

This skill provides instructions for running tests and lints for the Pigweed kernel (pw_kernel).

Building and Testing

• Use bazelisk: Always use bazelisk instead of bazel.
• Use --config: All kernel code must be built/tested with a --config argument. Configs are defined in //pw_kernel/kernel.bazelrc and are prefixed with k_.
• Iterate on one config: Switching --config can be expensive due to rebuilds. Prefer iterating and fixing issues on a single config before switching to another.

Common Configurations

Configurations are defined in //workflows.json under the kernel group (via kernel_host and kernel_device subgroups). Common ones include:

• k_host: Host builds and tests.
• k_qemu_mps2_an505: ARM QEMU emulation.
• k_qemu_virt_riscv32: RISC-V QEMU emulation.
• k_rp2350: Raspberry Pi RP2350 (note: may have no_test set).
• k_doctest: Rust doc tests (takes a long time to execute).

Running Tests

To run tests for a specific configuration:

bazelisk test --config=k_host //pw_kernel/...

To run a specific test:

bazelisk test --config=k_host //pw_kernel/kernel/tests:scheduler_test

[!NOTE] Use --noshow_progress --noshow_loading_progress to reduce output in agent contexts if needed.

[!TIP] Use --test_timeout=10 --test_output=all to catch tests which do not terminate.

Linting and Formatting

Rust Linting

The kernel build steps named like k_*_lint should be run to provide Rust linting for the code. These are defined in workflows.json.

Example for linting on host:

bazelisk build --config=k_lint --config=k_host //pw_kernel/...

Project-wide Formatting and Presubmit

Run these from the repository root:

• Format: ./pw format
• Presubmit: ./pw presubmit

When to use this skill

Use this skill when you need to run tests, lints, or verify changes in the pw_kernel module. This ensures you use the correct configurations and tools as defined by the project.