Since we are dealing with a business application, it is sometimes hard for developers to really know the implications on the rest of the program. Consequently, we introduced the following policy: Every single business-related task has to be validated by a business expert, a consultant in our case. So to finish a task the developer has to complete the following steps:
- Run and pass the unit tests.
- Build the application with version information included.
- Rename the executable to the name of the task.
- Place the executable in a common directory for finished tasks.
- Mark the task as finished in the task control tool.
Periodically a selected group of consultants check the finished tasks in the tool, run the related executables to determine whether the modifications are correct, and if they agree on the changes, they mark the task as verified in the task control tool. Once there are several verified tasks, the tasks are integrated to create a new release. There are several possibilities about integration periodicity. Some developers argue in favour of daily integration, others for integrating continuously. We decided to integrate once a week. The period depends on the amount of work your team is able to produce. If your team is big enough to complete a large amount of tasks every day, then integrate once a day. In my case I need a week to have a good set of verified tasks, so we create a new release every week.
A more agile approach says that a continuous integration is better. In my opinion it depends on the nature of the software you're developing. If stability is your biggest concern (and it is in my case), then I prefer to have somebody controlling every change that is made to the software. If velocity is the main concern, then is better if every member on the team can integrate its own changes. Also having somebody responsible of the integration process hides the complexity of the task to the rest of the team, than won't be bothered with the internals of the SCM tool.
Once a new release is created, the source code is labelled and a new baseline is created. Recently we have created a test group integrated by both consultants and developers. The group has created a big set of automated tests under Rational Test Suite that checks most of the functionalities of the application. Nowadays we are not yet covering all the functionality, but we're pushing to have a quite complete test suite. So before labelling a release we run the automated test suite (now it takes about 12 hours), and if it passes then we label the release.
Once the release is labelled, the ongoing tasks are asked to be updated to the new release so that developers work against the most up-to-date release.