By Lahiru Kasun — Associate Software Quality Engineer
This article is designed to support anyone interested in testing software that includes hardware components. My goal is to focus on the most important points that must be understood while keeping the content concise. So go and grab a cup of coffee and start reading this blog post.
What is an Embedded System?
An embedded system combines computer hardware and software to perform a specific function. Small standalone systems or large combined systems can both be embedded systems. They typically consist of a processor, memory, communication ports, and a power source. Examples of embedded systems include traffic lights, washing machines, vending machines, fitness trackers, and GPS systems.
How to test an Embedded System?
It is a testing procedure for examining both functional and non-functional features of embedded systems. Different levels of granularity can be used while testing embedded systems. It is common to utilize system unit testing, system integration testing, and system verification testing.
Different testing phases for Embedded Systems
System unit testing
Unit testing involves isolating and testing each module of the application. Bugs are considerably simpler to fix at the unit testing level than they are at the higher ones. Testing frameworks such as CppUnit and Catch2 can be used to perform unit testing in an embedded system. The cost of fixing a defect found during unit testing is lower than that of a defect found at a higher level.
System integration testing
This technique of testing is carried out in integrated software and hardware settings to accurately verify the system’s behavior. This expands the testing scope, and bugs that occur as a result of module interactions are often discovered during integration testing. This involves setting up communication interfaces, physically joining the hardware pieces, and making sure the specifications for the hardware and software work together. Integration testing is challenging since some defects can be related to hardware components. When the integration test cases get too complex to run manually or frequently, it is advised to automate them.
System verification testing
After the integration is finished, carry out thorough validation and verification at the system level. This allows engineers to assess if the system satisfies its high-level requirements when performed on a fully integrated system. This ensures that the system performs the required functionality precisely and consistently and that the hardware and software components interact seamlessly.
The user experience of an embedded system can be improved through non-functional testing. Non-functional testing reveals problems with security, reliability, speed, and usability. We can perform tests such as performance testing, security testing, usability testing, and compatibility testing depending on the requirements.
Common types of Embedded System defects
It’s challenging to locate and eliminate defects in embedded software. Following are some of the most common defects you might find when testing an embedded system.
Logic bugs
When a hardware device’s logic design or implementation deviates from the intended functionality or specification, it is known as a logic bug. Errors in design, coding, synthesis, or optimization can all lead to logic defects. By adhering to best design practices, utilizing coding standards, doing code reviews, and utilizing verification techniques, logic errors can be mitigated.
Timing bugs
Timing bugs are hardware defects that arise when a hardware device’s specifications or time restrictions are not fulfilled or followed. Design flaws, code faults, synthesis errors, optimization errors, and physical impacts can all lead to timing bugs. By utilizing coding standards, doing code reviews, adhering to best practices in design, and improving timing performance, timing issues can be avoided or fixed.
Power bugs
Power bugs show up when a device’s power budget or limit is exceeded by its power consumption. System failure, battery degradation, overheating, and performance decline can all be caused by power issues. By using verification techniques, adhering to best design standards, and increasing power efficiency, power bugs can be prevented.
Security bugs
When a hardware device’s security features or procedures are exploited or bypassed, security issues arise. Security features are designed to keep unwanted users from accessing, modifying, or harming the hardware equipment. System damage, system hijacking, data manipulation, and data leaking are all possible outcomes of security defects. By using verification techniques, adhering to the best design standards, and putting security countermeasures in place, security flaws can be prevented.
Software testing vs Embedded System testing
Although the software and embedded testing are similar, they differ in some significant ways. Systematic techniques are used in both types of testing, but software testing is less hands-on than embedded testing.
Challenges of testing an Embedded Systems
Environment constraints
Simulating a production-like environment can be challenging due to environmental challenges such as temperature, lighting conditions, wind, etc.
Hardware dependency
One of the biggest challenges encountered when testing embedded software is hardware dependency. PCBs, sensors, and Microcontrollers/microprocessors are part of an embedded system. Hence having fundamental knowledge about hardware devices is essential.
Software and hardware defects
Hardware defects can be identified in freshly created hardware. So the found defects are just not limited to software. It could potentially be a hardware issue.
Reproduce defects
In the case of an embedded system, defects are more difficult to reproduce. Because it involves both software and hardware when reproducing the defect.
Regular software updates
Regular software updates are required for embedded systems such as security fixes, kernel upgrades, different device drivers, etc. These updates can make bug identification difficult.
Conclusion
Software testing relies on a virtual model of the product, Whereas embedded testing must rely on both hardware and software components of the product. Compared to regular software testing, embedded software testing is significantly more challenging. In particular because of its dependence on the hardware environment. Therefore, It is necessary to do high-quality embedded testing regularly.
