Why automated testing is crucial for embedded Linux systems quality
When you’re building a Linux-based system for a particular device, using automated testing is crucial. It’s not just about making sure everything works; you also need to check how well the system performs, how stable the kernel is, and if the drivers are compatible with the device. This is especially important when you’re putting together different parts and customizing the BSP (Board Support Package).
Automated testing ensures that when you develop your Linux on your specific device, it meets the quality you expect. It’s the foundation for making the whole process of creating a product smoother. It helps catch problems early, reduces development time, and in the end, gives you embedded Linux systems that not only meet but maybe even surpass your expectations.
Ptest: a test suite for component testing
One notable solution for component testing is Ptest, an open-source framework provided by the Yocto Project. Ptest allows for building, installing, and running self-tests of upstream packages and provides standardized reports for analysis. Ptest is particularly useful for validating the functionality of individual components in an embedded Linux system.
LTP: another test suite for comprehensive embedded Linux testing
The Linux Test Project (LTP) serves as another valuable suite of tests, focusing on the global reliability, robustness, and stability of the embedded Linux system. While Ptest is more geared towards component testing, LTP dives deeper into the Linux system kernel. Despite the complexity and time-consuming nature of LTP tests, they offer a comprehensive evaluation of the system’s overall state, making them especially relevant in the context of embedded systems using specific BSPs.
The LTP test suite covers a large set of test cases like:
- Containers (namespaces)
- System calls
- Sockets
- Threads
- Basic commands (ar, cp, cpio, df, …)
- Real-time (latency, …)
- Math…
Creating custom tests for specific features
In some cases, existing test suites may not cover all the required scenarios. This necessitates the creation of custom tests for specific features like serial ports, displays, internet controllers, Wi-Fi drivers, etc. An example of this is automating tests for a real-time clock (RTC), including time reading, setting, and drift validation. While existing test suites may cover certain quality aspects, the implementation of custom tests becomes invaluable in ensuring the fulfillment of additional, specific requirements.
To make this happen, you need to set up a versatile automated testing environment. This involves having a test orchestrator that connects with the device under test. A console interface, like SSH or serial, helps run tests directly on the device. Adding extra interfaces, such as Bluetooth, boosts testing capabilities. The goal is to create a flexible environment that easily includes additional tests without making things complicated. That’s why, at The Embedded Kit, we developed Pluma – an automated testing tool. Pluma lets you organize all the tests you need using pre-built interfaces and custom Python code, making automated testing comprehensive and adaptable. And, of course, Pluma contains a dedicated test suite to ensure embedded Linux systems quality.
In conclusion, a well-defined automated testing strategy is essential for achieving high-quality embedded Linux systems. It starts with a clear testing strategy, defining roles, considering the testing environment, and selecting appropriate reporting tools. Developers play a crucial role in this process, and integration with continuous integration environments should be seamless. While technical challenges are surmountable, the key lies in establishing a robust, long-term automated testing solution that aligns with the product development goals. By leveraging existing suites and creating custom tests, embedded system developers can enhance the quality and reliability of their Linux-based solutions.
