Using the Test Mode to Populate Test Data in Web Dynpro 
A composite application is composed of the following three layers:
Process
User Interface (UI)
Business Logic
Web Dynpro (WD) is used to develop the UI layer. WD works on a model-driven approach i.e., the business logic available as services need to be first imported as WD models in the WD project, before creating the UI. This results in the need to have the business services available as a prerequisite to create a WD application. Also in order to test the created application, the business services must have a valid implementation and must be up and running.
The requirement of a valid implementation gives rise to two major constraints for developing a Web Dynpro application, which are as follows:
Availability of service definition to create an application.
Having a service implementation in place to test and run an application.
The first dependency cannot be avoided; however, you can avoid the second dependency using the Test mode feature.
A Test mode is a mechanism used to provide dummy data to the WD application. To run an application in Test mode, you do not need:
The service implementation with actual data. You can also use the Test mode in conjunction with actual data for complex applications that use a series of services with the implementation of one or more missing services.
A runtime configuration
Prerequisites
You have:
Configured the AS Java Server in the Developer Studio
For more information, see Configuring the Application Server in the Developer Studio
Imported either the Adaptive Web Service model or Enterprise JavaBean model depending on the model that was used in the application.
For more information, see Importing Adaptive Web Service Models
For more information, see Importing Enterprise JavaBean (EJB) Models
Procedure
Enabling the Test Mode
In the Web Dynpro Explorer, select the required model.
In the context menu of the selected model, choose Enable Test Mode.
Once the Test mode has been enabled, a test mode icon appears over the icons of model and model classes in Web Dynpro Explorer.
A set of default dummy data is generated for the properties of these model classes. You can view and edit this data by opening the corresponding model class editor and navigating to the Test Data tab. This test data can now be used to run the application.
Note
Test Mode is enabled only for model classes that are directly or indirectly related to the Response model class and have at least one model class property.
Test Mode only feeds dummy data and does not maintain any execution logic. Hence, irrespective of the input to the request model class, the output would always be the set of dummy data that were created in the model class editor.
The set of dummy data is restored even on disabling the Test Mode. However, on model re-import a fresh set of dummy data is generated.
Running the Application
Once an application with the Test Mode enabled models is created, you can simply deploy and run these applications without performing any runtime configurations.
Select the application and choose Deploy new Archive and Run.
Disabling Test Mode
Once the service implementation is available, the same application can run with the actual data by simply switching off the Test Mode for the model.
In the Web Dynpro Explorer, select the required model.
In the context menu of the selected model, choose Disable Test Mode.
The Test Mode for the model in now disabled.
Note
Test mode is not available in productive applications when the archives are created in the Central Build Server (CBS).
Enabling or disabling a Test Mode does not have any effect on the created application and the same application can be run without being altered with test data as well as actual data.
Result
As the Test Mode feature can be enabled and disabled as and when required, an application developer can develop and test a Web Dynpro application without the need to have a service implementation up and running.