When testing your plug-in, you have the ability to manage and select the list of plug-ins that you want to launch with on the Plug-ins Tab of the launch configuration.
The Launch with combo box allows you to configure the way the JUnit Plug-in Test is launched. The options are explained in more detail below.
The all workspace and enabled external plug-ins option is the default setting. With this option, the runtime Eclipse application you are launching will be made up of all the workspace plug-ins and all the plug-ins that are explicitly checked on the Window > Preferences... > Plug-in Development > Target Platform preference page. This option requires little maintenance because the list of plug-ins is maintained by PDE and updated prior to every launch as plug-ins are created or deleted in the workspace. This option is recommended when the Program to Run setting on the
Main tab of the launch configuration is set to the default product or default application of your target.
The plug-ins selected below only option is typically used when you are in headless mode or when you are testing an RCP application that uses a subset of the plug-ins from the workspace and target. This setting requires more maintenance than the other options since, you have to ensure the list of selected plug-ins is up-to-date when you add or remove a plug-in from the workspace. There are several buttons available to help you select plug-ins, including an Add Required Plug-ins button. The Add Required Plug-ins button should be used often to ensure the subset of plug-ins you have selected is complete.
Please note that if a workspace plug-in has the same ID as a target plug-in, the workspace plug-in overrides its target counterpart. This behavior can be overridden when using the second option; since, you can deselect a workspace plug-in and select its target counterpart.
The Validate Plug-ins functionality, which can be invoked via the button located at the bottom right corner of the Plug-ins tab, analyzes the selected set of plug-ins to find launching startup problems. For instance, missing dependencies, unsatisfied execution environments, incompatible platform filters are a few of the potential problems that may prevent your plug-in from running.
By checking the Validate plug-ins automatically prior to launching option, PDE will run the Validate Plug-ins function prior to every launch. If problems are found, an error dialog will appear for you to examine and you can choose to either continue the launch without correcting the problems or cancel the launch to rectify the issues. Otherwise, if no problems are found, the launch proceeds as normal.