Embedded Testing

Embedded means one object bounded by another. Embedded systems are computer hardware with embedded software. These are electronically controlled devices that may contain other computer devices. 

The software and hardware are coupled to perform operations like retrieving, processing, storing, and controlling data in variable electronics-based systems. 

Embedded systems can have the following built-in components:

• Microcontrollers
• Memory: Primary(RAM,ROM) and Secondary(hard disk, CD)
• Input devices(keyboards, scanner)
• Output devices(printer)
• Interfaces
  
  

What is embedded testing?

Embedded testing is a technique that verifies the functional and non-functional features of the hardware and software in an embedded system. The sole purpose is to validate hardware and software so that the end product meets the user requirements/specifications.

How to perform embedded testing?

Embedded systems may contain in-built computing systems to perform specific tasks. Even the users need to be made aware of these integrated devices.

Testing requires specific hardware-

• Specific inputs and outputs
• A system that has a different architecture
• Target that has limited resources 

So, testing embedded systems differ from the conventional software testing process in various aspects. To perform embedded systems efficiently, the testing approach must cover functional, integration, and performance testing aspects. Now, in general, there are four reasons to try the software, they’re:

1. Finding any bugs, errors, or defects.
2. Reducing risks for both the users and the company.
3. Minimizing the development and maintenance cost.
4. Performance improvement.

Embedded system testing requires expertise in software and hardware testing. Let’s check the process to perform embedded testing.

1. The software is fed with a specific dataset.
2. A piece of the software is executed.
3. The state of the software is observed.
4. The outputs are checked and compared to determine whether it meets the expected outcome and aligns with the requirements and functions without any crashes or flaws.
   
   

Types of Embedded Testing

Based on the system type and usage in the software industry, we can consider five types of embedded testing.

1. Software Unit Testing
   Every software contains units or modules. Unit testing determines whether each unit code executes as intended. During the development phase, a developer is responsible for monitoring unit testing. 
   
   After the module specifications are set, and test cases are implemented, it is often carried out in a peer-review model. The accuracy of each unit’s code, whether it be function, object, or module, is independently validated.
   
   

2. Acceptance testing
   This type of testing is conducted to see if the software meets the user’s requirements. A client or any customer organization member may perform acceptance testing. The main focus of the testing is only on those features or functionalities that customers often use. The test validates what exactly the system is supposed to do.
   
   

3. Integration Testing
   This type of testing tests the interaction between the hardware domain and software components. This includes analyzing how the software and the integrated devices interact. 
   
   The unique feature in this scenario is the creation of the actual environment parallel to which the software runs. The procedure cannot be carried out in a simulated environment. Thus, testers consider integration testing a critical task.
   
   

4. System unit testing
   Small units of the system undergo testing. The units are tested in a comprehensive environment, including platform-related components like interruptions, tasking mechanisms, etc. It allows testers to focus on a particular part of the system at a time. The system’s resources are evaluated to determine their ability to support the embedded system’s operations.
   
   

5. System integration testing
   The procedure involves testing the entire system, i.e. a multi-component system within a single node. The purpose is to assume that the system and the sub-systems are mostly correct. This testing finds bugs in the interface or unexpected flaws that lead to system issues.
   
   

6. Validation testing for systems and subsystems
   This type of testing ensures complete implementation of the entire embedded system and the subsystems. The aim is to check whether the output meets the requirements of the external entity. The external entity can be any person, a device connected to a telecom network, or both.
   
   

7. Regression testing
   When changes are made to the system, regression testing is performed to ensure that the changes have not introduced any new issues or errors. It assures that the product is working fine with added features, bug fixes, or changes to existing features. By automating the regression testing process, QA professionals can save time and effort.
   
   

8. Load testing
   Load testing involves testing the system under heavy loads to see if it can huddle large amounts of traffic and usage. In other words, it determines the system’s performance when multiple users use it.
   
   

9. Stress testing
   As the name suggests, stress testing tests systems under stress or extreme conditions, i.e., testing beyond the normal operational limits. It determines the stability of the system in unexpected situations.
   
   

Difference between Embedded testing and Software testing

Why Embedded Testing?

Let’s see the importance of embedded testing in delivering reliable and high-quality embedded systems.

1. It identifies and resolves potential issues to ensure the system’s security, reliability, and performance. This is a must, as embedded systems are used in safety-critical applications.
   
   
2. Thorough testing reduces risks, prevents system malfunctions, and safeguards users from potential harm. Thus, saving them from severe consequences.
   
   
3. It is essential for validating compliance with industry standards and regulations.
   
   
4. Effective embedded testing allows developers to maximize performance by detecting possible issues, memory leaks, or excessive battery consumption.
   
   
5. Embedded testing in a real-time environment ensures that complex tasks are completed within the required period and avoid delays in system performance.
   
   
6. It ensures proper interaction and functionality between the software and the hardware.
   
   
7. Developers can detect and fix issues with hardware interfaces, allowing seamless interaction of the embedded system.
   
   

Common testing techniques for Embedded Security Testing

1. Penetration software testing- Checks for system vulnerabilities and exploits system flaws to see how attackers can harm the system’s security.

2. Fuzz software testing- Feeding the system with an input to spot any unexpected behavior. Fuzz testing detects any code injection, overflows, and other risks.

3. Code coverage analysis- Code coverage analysis involves scanning the source code to look for potential vulnerabilities.

4. Protocol analysis- Tests the system’s communication protocols to identify potential security issues.

5. Risk analysis- Identifies potential threats and vulnerabilities and evaluates risks to the system. From the risk analysis, security controls are implemented in the system.
   
   

Challenges in Embedded Testing

Challenges that developers can face during embedded software testing:

1. Hardware dependency is suffered during embedded software testing due to limited access to hardware.
2. Developers need to ensure the system update never fails.
3. Most embedded software components are open-source, not developed internally, and need proper testing.
4. Selecting the right software and hardware component is essential for embedded systems to work reliably.
5. A high ratio of defects can be detected during software development for new hardware and software.
6. Embedded testing evaluates every defect occurrence considerably higher than in a traditional scenario.
   
   

Embedded systems require constant upgrades like security fixes and different drivers, making bug detection difficult.

As consumer use embedded system applications for critical purposes, so few factors needs to be considered before market release:

• Real-time responses
• Host (target) systems and development environments must be kept apart.
• Architectures for deployment are not standardized
• Systems under testing don’t have established interfaces
• Strict requirements for fail-safes
• High expenses of finding and correcting flaws
  
  

Embedded Testing Tools

Below are some features to consider before choosing the right embedded testing tool.

1. Tools that can perform all levels of embedded testing( unit, integration, and system testing).
2. The more thorough coverage testing, the less chance of unexpected breakdown.
3. Tools that ensure embedded systems meet their performance and security requirements.
4. Tools that integrate with a continuous build environment.
   
   

Some embedded hardware testing tools:

1. Oscilloscopes: Analyze and measure electronic signals in hardware designs.
2. Logic Analyzers: Capture and display electronic signals in hardware designs.
3. Boundary Scan Testers: These offer minimally disruptive testing of digital signals in hardware designs.
4. Protocol Analyzers: Analyze and decode communication protocols in target hardware design.
   
   

Some embedded software testing tools:

1. Ceedling: It is an open-source software testing framework. It allows automated testing of embedded C applications.
2. Unity: Software testing framework for C and C++ embedded applications.
3. LDRA and Paradoft: Both are automated software testing tools for embedded system verification and validation.
   
   

Conclusion

Testing is vital in development, as end-users cannot change software or control hardware components. Embedded testing is quite a challenging task compared to regular software testing due to its hardware dependency. Quality and reliability are essential in embedded systems, making testing crucial for developing embedded systems.

This type of testing improves both hardware and software performance. Embedded testing is crucial to provide security in medical, railway, and more software solutions. This reduces the risk for both users and companies utilizing embedded systems.