Graphic User Interface Testing (GUI) testing is the process of ensuring proper functionality of the graphical user interface (GUI) for a specific application. This involves making sure it behaves in accordance with its requirements and works as expected across the range of supported platforms and devices.
Modern computer systems are generally designed using the ‘layered architecture approach’:
This means that the core functionality of the system is contained within the “business logic” layer as a series of discrete but connected business components. They are responsible for taking information from the various user interfaces, performing calculations and transactions on the database layer and then presenting the results back to the user interface.
In an ideal world, the presentation layer would be very simple and with sufficient unit tests and other code-level tests (e.g. API testing if there are external application program interfaces (APIs)) you would have complete code coverage by just testing the business and data layers. Unfortunately, reality is never quite that simple and you often will need to test the Graphic User Interface (GUI) to cover all of the functionality and have complete test coverage. That is where GUI testing comes in.
Testing of the user interface (called a GUI when it’s graphics based vs. a simple text interface) is called GUI testing and allows you to test the functionality from a user’s perspective. Sometimes the internal functions of the system work correctly but the user interface doesn’t let a user perform the actions. Other types of testing would miss this failure, so GUI testing is good to have in addition to the other types.
There are two main types of GUI testing available:
This is often what people associate with GUI testing tools. With analog recording, the testing tool basically captures specific mouse clicks, keyboard presses and other user actions and then simply stores them in a file for playback. For example, it might record that a user left-clicked at position X = 500 pixels, Y = 400 pixels or typed the word “Search” in a box and pressed the [ENTER] key on their keyboard.
Relative analog recording is one type of analog recording where the positions of interaction events are recorded in relation to the top-left corner of the application's window:
Absolute analog recording is the other main type of analog recording. Here, the positions of events are recorded relative to the top-left corner of the system screen.
The main benefits of analog recording are:
However, there are several major drawbacks to analog testing:
When you use object based recording, the testing tool is able to connect programmatically to the application being tested and “see” each of the individual user interface components (a button, a text box, a hyperlink) as separate entities and is able to perform operations (click, enter text) and read the state (is it enabled, what is the label text, what is the current value) reliably regardless of where that object is on the screen.
The main benefits of object based learning are:
However, there are some drawbacks to this approach:
So the best practices are to use Object Based recording that is more robust and reliable where possible and then use Analog recording to “fill in the gaps” where nothing else works.
Regardless of the approach taken, there are some general challenges with GUI testing:
It is generally recommended that you perform an early assessment of the technology that the application uses and see which UI controls and widgets are being used. In many cases you will have some non-standard UI controls and elements that testing tools may struggle to interact with. You need to do this assessment upfront before selecting a tool.
For example, on a sample Microsoft Windows system, the following different automated testing technologies are available:
Each technology that your application uses may require a different testing library that can understand how to recognize the UI objects, for example:
In theory you could automate 100% of your manual tests and replace with automated GUI tests. However, that is not always a good idea! Automated tests take longer to write than manual test since they have to be very specific to each object on the page. With experienced manual testers, you can write very high level instructions (“test that you can reserve a flight”) and they can test lots of combinations and follow their intuition much more quickly than you can record all the different automated tests.
However, computers are really good at automated mundane tasks. For example, testing that you can click on every possible page in the application and do it on all flavors of the operating system, web browser and screen resolution would take forever for a human, but would take an automated testing tool no time at all. Similarly, testing the login page with 1,000+ different login/password combinations is much more efficient for a computer to do.
So let’s say that we have decided to automate 20% of our test cases, great! There is only one problem - 20% means 20% of your test cases. But which 20% you may ask?
How about the 20% of test cases used most often, that have the most impact on customer satisfaction, and that chew up around 70% of the test team’s time? The 20% of test cases that will reduce overall test time by the greatest factor, freeing the team for other tasks. That might be a good place to start.
These are the test cases that you dedicate many hours performing, every day, every release, every build. These are the test cases that you dread. It is like slamming your head into a brick wall – the outcome never seems to change. It is monotonous, it is boring, but, yes, it is very necessary. These test cases are critical because most of your clients use these paths to successfully complete tasks. Therefore, these are the tasks that pay the company and the test team to exist. These test cases are tedious but important.
Sometimes when automating an application, you will meet a special UI control that is not handled by the testing tool that you are using (or maybe is not handled by any testing tool that you have tried). If you look for perfection, so that every single possible object on the page can be tested automatically you may end up frustrated, wasting time and possibly resulting in abandonment of the entire automation effort.
The solution is to be creative, if you can use analog recording for that one control, then maybe that is the best solution. Sometimes you may need to use a combination of techniques to simulate the user action, using special keystrokes to avoid the button in question. The goal is to improve your test coverage and make sure you find problems that need fixing, if that involves some creative solutions that are not “perfect”, so be it, the overall goal is still being met.
Obviously the first answer is to choose a tool that can automate the specific technologies you’re testing, otherwise your automation is doomed to fail. Secondly you should choose a tool that has some of the following characteristics:
Rapise from Inflectra is a great tool that meets these criteria, is very easy to use, covers a wide range of technologies (web, desktop, mobile and APIs) and is relatively affordable:
However whichever tool(s) you choose to use, make sure that your testers can try them out for at least 30 days on a real project to make sure they will work for your team and the applications you are testing.
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