Grey Box testing is a technique of software testing that uses a mix of black box and white box techniques. This type of test will usually be conducted with the system requirements, design specifications, documentation, and code available to the tester. The goal is to identify risks or potential problems in the design before coding starts.
In this blog post, I’ll outline some key points about how you can perform grey box testing techniques on your next project to help reduce risk and increase quality for your users.
What is Gray Box Testing?
Grey box testing is not a formal testing methodology. Rather, it is the combination of two methods: Black Box testing and White Box Testing (also known as glass box or clear box).
Black Box Testing
In black-box testing, the tester typically starts working with no knowledge of the code and tests based on user requirements, specifications, etc.
White Box Testing
With white-box testing (also known as glass box or clear box), the tester knows all about the internal implementation details or internal working structure of the source code. The goal is to test at this level: “can I break it by testing the implementation?”
Gray box testing combines these two methods to add value by focusing on the grey area between what is known and unknown. If you start with a blank slate (black box) without any knowledge of the code, how do you find bugs? On the other hand, if you know everything about how things are implemented (white box), how do you find risky areas to test?
Grey box testing helps bridge the gap between knowing nothing about the code and knowing everything.
Why use Grey Box Testing?
When doing software testing, you always run the risk of introducing bugs into production by finding and fixing bugs before the feature is complete. Having a way to find issues in design before code is written can reduce this risk.
Also, using grey box tests early on in the development of a new product or system lets you start putting together defects for your project. In agile development and lean manufacturing, it is very common to see bugs as a backlog item for the next sprint; grey box tests can be used for that purpose. This also lets you spend time on other items instead of just bug triaging after coding is complete, which will then let the team move faster through subsequent sprints.
Real-world example Of Gray Box Testing
Let’s look at a real-world example where we used grey box testing: the API for a payment platform. Our goal was to help our clients find issues in their design before coding started, which would then allow them to produce a low-risk and high-quality system that customers could enjoy. We were able to get far enough along with this testing to give them enough confidence to start coding.
The requirements for this project were:
New features will be created with the legacy APIs until we see they are stable over some time
The first feature offered was an existing one that had been in production since before this company went API-only. This meant that we would need to keep backward compatibility for the legacy functionality until we were confident that any changes to the API would not affect its stability.
The white box testing was not as clean-cut in this scenario, but we were able to refer to previous versions of the code base, old documentation, and look at what other companies (who had previously purchased these services) did with them.
Black box testing on the other hand was much easier. Thanks to a previous effort in simulating the end-user experience for this feature, we were able to simply replicate that same test, but with different data coming from the new API endpoints.
With these requirements and an understanding of how to go about grey box testing, we were able to contribute valuable feedback to the project early on in its development cycle. We were also able to maintain a fast rate of progress throughout the project, and our client was pleased with how smoothly this effort went.
Now that you have a basic understanding of what grey box testing is and why it may be useful, let’s look at some practical steps for implementing it:
How to Perform Gray Box Testing?
So how do you get started with grey box testing? Here are some steps that I recommend:
- Understand Your Objectives and Scope: Ask why you’re doing this work before getting bogged down in any of the details. Remember, grey box testing is not a formal process; it’s more of an approach that you can tailor to your specific project.
- Define Your Approach: Think about how you’ll conduct your analysis, and what information you need to collect in order to do so successfully.
- Collect Information: Select the appropriate approaches of gathering information based on the phase of the project you’re in, and what you have access to.
- Analyze: You may want to identify potential risks/problems using a risk matrix (described below).
- Implement: At some point, turn your analysis into action by automating it as part of your test plan.
Gray Box Testing Techniques
Now that you have an idea of why grey box testing is useful, let’s talk about some ways to implement it.
Gray box testing can be performed at any stage of an application’s lifespan. There are several methods you can use, as well as combination strategies to ensure all issues are addressed.
We’ll take a look at how you can gather information using four different gray box testing techniques:
- Matrix Testing
- Regression Testing
- Pattern Testing
- Orthogonal Array Testing
Matrix testing is one of the most common techniques used in grey box testing. It involves a risk matrix that scores each element with severity and consequence, to create a ranking system within which you can prioritize your effort.
Severity refers to the severity of the impact if that issue is enabled. Is it a show-stopper bug, or might it simply be an annoyance?
Consequence refers to whether or not there is recourse for the destructive nature of this bug to be exploited. For example, will you lose data in your system by exploiting this bug?
You then prioritize your work based on these matrix values. Don’t get too hung up on these numbers… they are just a guide to help you see where you might want to be focusing first. You’ll know more as you dive deeper into the application under test.
Pattern testing is a less formal way of identifying potential risks in design. It’s based on the idea that, if a pattern has been used before and it worked well for another project, it should work just as well here.
Identify common patterns that are being reused from other projects. For each of these identified components/patterns, ask the following questions:
Is there an existing pattern that can be reused in this project? If so, is it being used correctly? How will this new application differ from the original usage of this pattern? How do these differences affect how we use this particular pattern?
By going through each component individually and questioning its use, you can develop a baseline understanding of where risks may exist early on in the project.
Orthogonal Array Testing
This is another method used to identify potential issues early in the cycle. Orthogonal array testing helps to minimize rework by enabling you to determine if an issue has already been found and addressed before continuing forward with your testing.
This is done by defining rules that you can use to assess the application under test. These rules may be something concrete, like a specific class or function call; they could also be more abstract, such as an overall goal for your project. Depending on what it is that you are looking for in your analysis, this will have a great influence on the rules you define.
Regression testing is an approach to testing that focuses on the functionality of a specific application or module after changes have been made. It’s used in grey box testing because it helps identify potential issues caused by the changes you make as part of your project.
Similar to regression testing for black-box projects, you need to create a baseline environment that accounts for all of the features and functionality you want to analyze. Then, when changes have been made at a component level, you can work through your application again to see if changes elsewhere in the project affected those feature areas. You can then address them so that you don’t have any issues once you release the new system into production.
Gray Box Testing Challenge
While gray box testers are performing the gray box testing, they are facing several challenges and we are trying to mention below:
- Testers are not given access to the source code, which can result in missing certain critical vulnerabilities.
- Developers may feel like they are testing a grey box if they have already run a test case that is similar to their current one.
- It is challenging and time-consuming to thoroughly check every input, as there are many paths that will not be tested.
Advantages of Gray Box Testing
While there are many advantages of Gray Box Testing but some of the important ones are mentioned below:
- By using gray box testing, we can find out security issues at the early stage.
- It is also helpful to save time and cost of development project.
- It can reduce the possibility of testing time.
- By using a lightweight technique, it will be very helpful to adopt for the SMEs.
- We can cause some advantages during testing the requirement of the client as well.
- It is beneficial for the project management to use these techniques.
Disadvantages Of Gray Box Testing:
While using Gray Box Testing there are some disadvantages as well. A few of them are mentioned below:
- In the scope of organizations, we can’t find out all the risks and threats in a software application.
- For an expert in software industry it is very tough to test manually.
- There may be problem in testing the complex features in a software application.
- It would be a very helpful technique for the manual testing of an application.
- It is also difficult to understand the functionality of complex system in white box testing with enough time.
So Gray Box Testing has many advantages and disadvantages but it always depends on your requirements and what type of testing you want to implement in your project, which will help you to understand the importance of Gray Box Testing.
Testing is a critical process in the software development life cycle and there are many testing types, techniques, and methods available for this purpose but before implementing any testing we need to know about some benefits or disadvantages of specific technique or method because it’s very important for us that how much time our testing duration will be or what level of quality our testing deliver to us.
Perform grey box testing Using automated software testing tools:
Various tools can help in performing testing. A few of them are mentioned below:
- Chrome Dev Tools
Grey Box Testing Summary
So there you have it – an introduction to grey box testing! As I mentioned earlier, grey box testing is not a formal methodology. Instead, it’s an approach you can apply to your specific project. You might want to keep this approach in mind as you’re working on your next project and see how it could be applied.
What are your thoughts about grey box testing? Have you ever tried something like this or do you have a better approach to grey box testing? Share your thoughts in the comments below!
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