Process of Embedded Testing 

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Embedded testing is a procedure used to examine the functional and non-functional characteristics of the software and hardware in an embedded system and ensure the finished result is free from flaws. In addition, embedded testing aims to confirm whether the finished piece of embedded hardware and software satisfies the end-user requirements. Examples of embedded systems are ATMs, Flight control systems, Washing machines, Navigation systems, Engine power management systems, ETC.

This article will help you understand everything related to embedded testing. After going through this article, you will know the types of testing, why and how to do the testing, and the challenges you can come across during the testing.

Critical factors of Embedded Testing

Let’s see the essential factors of embedded testing

Key FactorsEmbedded Testing
TargetEmbedded testing is executed on both software and hardware
TypeIt is based on both BlackBox and white box testing.
TestingIt is conducted to test how well the software utilizes the hardware to meet the desired requirement.
Area of applicationIt is used on Embedded System
ProcessIt is primarily a manual process. Also, for evolving long-term Systems, Automation is considered to facilitate the testing process and minimize long-term testing costs.


An embedded computer software called firmware allows for the control, monitoring, and data manipulation of manufactured systems and goods. Devices’ low-level control software is provided by the firmware built into them. Computers, mobile phones, peripherals, embedded systems, and so on are some devices that include firmware.

The importance of firmware testing is the assurance that a firmware system satisfies its requirements in terms of functional correctness and performance operational and implementational qualities.

Types of Embedded Testing

Testers do high-level testing in two components. One is Hardware, and Secondly Software.

An Embedded System testing is done on many levels throughout its development process depending on its uses of the software/hardware development life cycles(SDLC) model. Below are some of the testing-level instances.

Hardware Testing

It involves checking the hardware quality (PCB, Components) to ensure that it fulfills the client’s/customers’ needs and compliance requirements (Hazardous issues). Hardware is tested at the PCB Manufacturing level. Primarily Firmware/Bootloader is also being used to check the functional characteristics between MCU peripherals, components, and circuit connections at the research and development level. Software or firmware gives life to embedded systems and provides control to operate as required.

Unit Testing

In unit testing, testers execute the test on a piece of software’s code to determine whether each unit’s code works as intended. Completing the isolation and checking the accuracy of a specific part of code during the software development phase. Function, module, object, procedure, and method are all examples of units. Mostly developers do the unit testing and subsequently hand up control to a peer-review mechanism. The creation of module test cases comes after establishing the requirements.

The module created for the test includes a framework of detailed facts about the real-time operating system (RTOS), software codes, information about communications, mechanisms, interrupts, etc. From this point on, sending and using a message via the RTOS message queues using the point of control protocol. The developer or system integration team then looks at the system resources to see whether the system can support the execution of the embedded system. The tester uses Gray box testing to carry out this process.

Integration Testing

Software integration testing and hardware integration testing are the two subcategories of integration testing. It includes testing how software and hardware interact with one another. Run this test as well to examine how software and integrated peripherals interact.

The conduction of Embedded testing in a natural setting akin to a software environment. Most testers consider embedded testing a crucial duty since it is hard to do thorough testing in a simulated environment. In this procedure, each node has components from many subsystems. Implementation of the Control and Observations Points as a combination of RTOS and network communication protocols, including RTOS events and network messages.

System Testing

System testing validates complete embedded-system (end-to-end) behavior. The tester validates the system’s functional and non-functional characteristics against requirement specifications. System functional testing involves supplying the correct input and comparing the output with the expected result/operational requirements. Functional testing mainly includes “black box” testing and is unconcerned with the application’s source code. System testing is done in a testing/simulated environment and by an independent tester.

Acceptance Testing

The main objective is to validate the complete system and whether it serves the user’s purpose for developing the product.

Due to a lack of understanding of product objectives or gaps in requirement specifications, an end product might not meet with user’s expectations or needs. Gaps in requirements can escalate to the design phase and the complete system, leading to dissatisfactory outcomes.

Another thing is a validating system in the testing environment only sometimes means that it will behave correctly in a production environment or entire field. Here acceptance testing comes in place. Acceptance testing provides confidence in the system’s readiness as this test is mainly performed in a simulated or natural environment and from the end user’s and regulatory context, needs, and satisfaction. Some common forms of acceptance testing are below, where the main variances are intended users and testing environment:

  • User acceptance testing (UAT): This testing typically focuses on the validating system for the intended user in an actual or simulated environment.
  • Operational acceptance testing (OAT): This testing validates the system from an operational aspect where intended users are administrative and maintain a product staff. This testing is done in a (simulated) production environment and focused on operation aspects.
  • Contractual and regulatory acceptance testing: The main objective of contractual and regulatory acceptance testing is to build confidence that contractual or regulatory compliance has been achieved. These testing results and processes are witnessed and audited by regulatory agencies.
  • Alpha and beta testing: Alpha testing is performed at the developing organization’s site, by potential users, or by an independent testing team (not the developer). In contrast, beta testing is performed by potential or existing customers in a natural field/environment.


In embedded software testing you have to face a few challenges while doing embedded software testing. Some of them you’ll see listed below.

Challenge 1-Hardware reliance

Testing is a significant difficulty since embedded software depends on the hardware device installed. The hardware platform may not be accessible at the beginning of the testing process. Testers make these early activities without access to the system hardware platform. Occasionally use emulators and simulators as a workaround. Still, there is always a danger that they won’t accurately reflect the behavior of the actual device and will offer an impression of system performance and usability that might eventually cause more severe problems.

Challenge 2-Open-source applications

It implies there isn’t a thorough test if embedded software is open source and didn’t make with internal development. However, a wide variety of test combinations and subsequent situations are available.

Challenge 3-Defects in hardware and software

When developing new software, you can find many hardware flaws, not just limited to software but also hardware.

Challenge 4-It’s difficult to reproduce errors

Because embedded systems imply the replication of events in software and hardware, it is more challenging to duplicate flaws. As a result, we must consider every flaw incidence during testing at a considerably higher degree of analysis than in a typical instance.

Furthermore, obtaining this reproduction analysis data necessitates deliberate system modification to uncover the fundamental source of the errors.

Challenge 5-Continuous software update need

For embedded systems, routine software updates are necessary for kernel upgrades, security patches, various device drivers, etc. However, it is challenging to find the problem because of any limitations in these upgrades. Therefore, the construction and deployment process also becomes more critical.

Challenge 6-Instrument qualification

Knowing that the testing tool yields reliable findings is beneficial if you must certify the embedded software you’re creating. Software testing tool suppliers can qualify their devices to give this assurance. This functionality is crucial when working with safety-critical software, such as avionics software.


Due to its reliance on the hardware environment, frequently needed to carry out high-quality software testing, embedded software testing is substantially more challenging than general software testing. Embedded software testing is rigid without specialized tools. Therefore, it is advisable to choose automated software testing since embedded automated testing enables faster, one- or the two-hour resolution of software bugs. We will cover Automated testing in a future post.

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