White Paper. Model-View Architecture for Test Automation. Author Naman Singhal 24 October 2013

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1 White Paper Model-View Architecture for Test Automation 24 October 2013 The objective of the present paper is to present a solution (a test automation framework) with which test automation can be done very effectively and in a faster manner. The presented solution can be very useful in the test automation thus generating good ROI to the organization. Author Naman Singhal naman.singhal@crestechglobal.com Visit us at:

2 Abstract Now a day, WPF (Windows Presentation Foundation) is widely used technology for software development because of its rich UI interfaces, easier animations and special effects. There are many tools i.e. QTP, TestComplete available for test automation in the market that can interact with WPF objects. But WPF object identification is the main challenge in the automation process. Tools like TestComplete have very complex object repository structure that is not feasible to maintain frequently on the fly and QTP is very much slow and non reliable in WPF object identification. The objective of the present paper is to present a solution (a test automation framework) with which test automation can be done very effectively and in a faster manner. The presented solution can be very useful in the test automation thus generating good ROI to the organization. Visit us at:

3 Introduction to Model-View View Model (MVVM) pattern: The Model represents the actual data and/or information. An example of a model might be a contact (containing name, phone number, address, etc.). The key to remember with the model is that it holds the information. Model may or may not contain the business logic. If business logic is kept separate from the model, then it is encapsulated in other classes that act on the model. The View is what most of us are familiar with and the only thing the end user really interacts with. It is the presentation of the data. For example, a date might be stored on the model as number of seconds since midnight on January 1, 1970 (Unix Time). To the end user, however, it is presented with the month name, date, and year in their local time zone. A view can also have behaviors associated with it, such as accepting user input. The view manages input (key presses, mouse movements, touch gestures, etc.) which ultimately manipulates properties of the model. The Model-View or controller is a key piece of the triad because it introduces Presentation Separation, or the concept of keeping the nuances of the view separate from the model. Instead of making the model aware of the user's view of a date, so that it converts the date to the display format, the model simply holds the data, the view simply holds the formatted date, and the controller acts as the liaison between the two. The controller might take input from the view and place it on the model, or it might interact with a service to retrieve the model, then translate properties and place it on the view. The Model-View also exposes methods, commands, and other points that help maintain the state of the view, manipulate the model as the result of actions on the view, and trigger events in the view itself. Fig-2: Introduction to MVVM The View and Model communicates via Model-View through data-binding, method calls, properties, events, and messages.

4 Business Case: A travel giant product development company is developing software using WPF technology, to sell the flight tickets in different markets across the globe. The application is required to have a complex and very dynamic user/ui interfaces. Thus it was no surprise that view controllers of the UI of application are going to change very dynamically through the development process and test automation process is going to be challenging like anything. The Challenge: To test the application frequently in an agile development environment, QA team decided to go for test automation using a renowned tool called QTP (On client s highest recommendation for the tool). Since objects in the application were getting changed very frequently making the situation for QA team worsen in maintaining the script and object repository as well as meet the pace in agile development. QA team had to fight also with the recognition of WPF objects as QTP was not very fast in recognizing the WPF objects. In short, list of challenges faced by QA had following points: 1. Complex Object Structure Leading to Object repository maintenance 2. Time taken to identify objects using Automation ID/Other Properties 3. Objects Property changing from release to release high script maintenance 4. Object Type(s) changing from release to release 5. Overall execution time The Analysis: A thorough analysis of the situation demanded to follow an approach which provides faster execution and less maintenance in script and object repository. This gave inspiration to QA team to use the Model-View architecture in Test automation. In the Model-View architecture, the view and the Model-View communicate via data-binding, method calls, properties, events, and messages, and models and properties in the Model-View are updated from the view via two-way data binding. After identifying the required views, or controls; the libraries can retrieve the Model-View. The Model-View will then provide a leeway to perform most of the operations, including reading current state of the screen. Driver script on QTP will consume the API contracts exposed by the WPF harness to perform test operations and read current state of the screen. For example, when Login button on the login screen is clicked, it calls submitcredentials function present in the Model- View of application which further goes to model to check the authenticity of provided username and password and lets the user login the application. In the automation exercise if we can call submitcredentials function from the Model-View after setting username and password then it will do the required task of login. For this the QA team had to make some screen parsers which could interact with application UI and so as to automate the end to end business processes test cases using QTP. The automation process required a controller library which can communicate with application in a faster manner, less maintenance in case of UI change, and an automation framework using QTP using those controller libraries to work on application.

5 Solution: After going through some brain storming meetings, finally QA team came to a solution to showcase to client. Solution is described in the below diagram: Fig1: Model-View concept in Test Automation An extra layer named screen parsers is added in between automation tool and Application Under Test (AUT). Those screen parsers are created using C# or VB.net. But QTP could not able to execute the code until those screen parsers was converted in the form of DLL. The collection of DLL is known as controller library. This controller library contains functions that act as liaison between application s View and Model. QA team named this controller library as Model-View controller library. This Model-View controller could take the user input to manipulate the model of application, read the state of application and view of application to verify the user input with the current application model and trigger events in the view itself.

6 Technical Architecture and Implementation: Test Scenario: In a test case, user opens login screen of application and enters text in the Login Id and Password fields and clicks on the Login button to login the application. Technical architecture of Login Screen: During the execution of the scenario a lots of things are performed in the background process. As user opens the login window, the visible property of the login window sets to True in the business logic of the application. IsLoginWindowVisible method from the DLL library checks visible property in the business logic and returns True or False to QTP which can be used for further validations and reporting. Similarly When user enters text in the text fields using PopulateFields from DLL library, an event to populate the fields gets triggered by the view which ultimately calls the function from application codebase that captures the user input in the business logic of application and when automation script executes BeginLogin functions on the Login button, it is similar to clicking the Login button and a appropriate function in the business logic is called to get the login task done on the click event of Login button. Fig3: Login Scenario example Automate the given test scenario: Step 1: Open the Login screen. When the login screen gets opened, we can check the visibility of the screen through visible property exposed by code base of application. Step 2: Populate the Login Id and Password fields. Script will take relevant inputs from any external source (Excel sheet, database, data files) and pass to the PopulateFields method in the controller library which will fix those text fields through data binding in the business logic. Step 3: Validate that Login Id and Password fields are successfully populated. Script will use ReadScreen method in the controller library and will create an xml file of properties and their values exposed by the application business logic. Now script will get property values of objects from the xml file and will validate against the user input. Step 4: Click the Login button. Script will call the BeginLogin method in the controller library which will again call the function from application codebase which is supposed to be called on the click event of Login button. Step 5: Exception handling. If Password Expire Notice comes then script will use the ByPassExpiryWarning to handle it.

7 Fig4: Technical Implementation

8 Challenges vs. Benefits: 1. Complex Object Structure Leading to object repository maintenance: In this approach, there is no Object Repository is created in QTP so object repository maintenance is reduced to 0%. 2. Time taken to identify objects using Automation ID/Other Properties: In this approach, XML of screen objects is created by reading the screen and converting their properties into XML in the form of nodes. Now QTP script communicates with XML to identify object properties so as reducing the time taken for object identification. 3. Objects Property changing from release to release high maintenance: Only few more validations points are required to add or remove from the script codebase based on the changed Object Property. 4. Object Type(s) changing from release to release: If any Object type is changed to another type then the changes would be done in the controller libraries not in the QTP script. For Example, if Radio group control is converted into drop down control but the data binding remains the same then no QTP script maintenance as well as controller library update would be required. If data binding also gets updated then only change in controller library would be required. 5. Overall execution time: As there is no direct communication between QTP and application, no OR and faster object property identification through XML, the overall execution time would be reduced by 50 60%.

9 References: About Author: Author is working as Sr. Quality Engineer in automation group of Crestech Software Systems Pvt. Ltd., a leading company in Software Testing and Quality Assurance domain. Author has worked across many technologies and different domains (BFS, Travel, and Insurance). He has a vast experience in automation with QTP and VB Scripting and framework designing.

10 Appendix: Business process test case: Represents the actual business process. A business process can be an individual business process or a combination of several processes. GUI: Graphical User Interface. Keyword: a keyword is a word or an identifier that has a particular meaning to the underlying tool. QTP: Quick Test Professional is a commercial test automation tool developed and licensed by HP. UI: User Interface. XML: Extensible Markup Language. WPF: Windows Presentation Foundation is technology by Microsoft for application development. QA team: Quality Assurance team DLL: Dynamic Link Library Object Repository: While recording, QTP stores the properties of the object in a file called object repository.