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Re: [agile-usability] Add an agile twist to your software configuration management process

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  • PPWilliamson
    Great article and thank you for sending it. Some very, very excellent SCM practices discussed here. Regards tester384 wrote: Breaking
    Message 1 of 2 , Feb 7, 2006
      Great article and thank you for sending it. Some very, very excellent SCM practices discussed here.

      tester384 <tester384@...> wrote:
      Breaking with Tradition
      by Steve Berczuk

      We do not usually associate the words "simple," "dynamic," or "agile"
      with software configuration management (SCM), but in many cases a
      simple, dynamic, and agile SCM process can greatly improve the
      productivity of a team. SCM gives you the ability to identify and
      control changes to your source code and reliably build a version of
      an application from a point in time. Agile SCM further enables you to
      integrate frequent changes, adapt to these changes, and get feedback
      on how they affect the quality of the system that you are building.
      To support feedback, agile SCM processes emphasize frequent
      integration and testing at all levels, in addition to the traditional
      SCM areas of build, release, and version management.
      Common Mistakes

          Software configuration management is definitely beneficial, so
      why are people often frustrated by it? The answer is that teams tend
      to misapply SCM in one of two ways: too much process or too little
      process. Ironically, one is often the consequence of the other.

          With too little process, there's no mechanism in place to correct
      mistakes. The codeline quickly degrades, so rules and procedures are
      added to reduce risk. When too many are added, the workflow is
      disrupted instead of supported. Despite a sense of security, errors
      still make it past development and are discovered much later. Since
      the context for the error has been lost, it is more difficult and
      more expensive to fix. See the StickyNotes for a link to the
      article "The Illusion of Control" that explains how the attempt to
      gain control by adding rules often backfires.

          Too little process is often a reaction to witnessing the perils
      of too much process. Teams avoid anything that looks like SCM and
      lose the coordination advantages that SCM provides.  It appears that
      they are making progress, but they have no way to verify that the
      changes made in one place don't interfere with work elsewhere. 

          To establish an appropriately agile SCM process, you need to
      overcome your fears and adopt practices that fit your development

      Agile SCM Practices

          To maintain a quality codeline and to be more productive, agile
      teams rely on communication, frequent integration, and the resulting
      feedback-using just the right amount of process.  Some agile
      practices that you can use even in a non-agile environment are:

      Working on a single active development line
      Working in private workspaces
      Using continuous integration
      Performing frequent testing
      Deploying Frequently
          Some of these practices cause worry among those who are used to
      more traditional approaches to SCM ("Don't you lose stability by
      committing changes so frequently?"). Agile SCM allows more errors to
      occur but reduces risk by catching and correcting them more quickly,
      before they can do harm.

      Active Development Line

          Some teams allow developers to work on branches in an attempt to
      preserve the integrity of the main codeline. The branches cause
      deferred integration, which makes development more difficult since
      many problems surface during integration, long after they could have
      been detected. In contrast, an active development line is a single
      codeline to which every team member commits changes.

          For a single active development line, you need:

      A culture that encourages finegrained, frequent check-ins
      Optimistic locking
      The supporting practices of private workspaces, continuous
      integration, and frequent testing
          Private Workspaces

          Team members do need some degree of isolation to allow
      uninterrupted work. Developers should have a workspace where they can
      control when to accept changes. To create a private workspace:

      Provide resources (disk space, database space, server software) that
      allow a developer to run a complete system. Some teams use shared
      components either in an attempt to save space or to prevent people
      from delaying integration. Space is cheap compared to developer time,
      and forced integration disrupts developer flow, hurting productivity.
      Set up a mechanism to allow a team member to quickly create a
      workspace from a repository. The process should be as automated as
      possible, so that all developers' environments are consistent.
      Provide a private build process that mirrors the integration build so
      a developer can evaluate his changes before committing them. Define
      the build process early in the development lifecycle.
      Have a policy in which developers resynchronize their code and build
      and test before committing changes. These precheck-in tests should
      run quickly and be automated to ensure they are run consistently.
      Continuous Integration

          A continuous integration system runs a build moments after
      anyone's check-in, executes more exhaustive tests, and notifies the
      team if something is broken. This allows team members to detect
      integration issues that might have slipped in despite their earlier
      best efforts. There is a variety of continuous integration tools
      available, and most are fairly straightforward to set up. In the
      absence of an automated tool, you can start an integration build
      manually every few minutes. The cost of setting up this process is
      small relative to the lost productivity caused either by a lingering
      mistake or by ill-conceived attempts to prevent mistakes.

      Frequent Testing

          An active development line can degrade quickly if continuous
      integration checks only that the codeline compiles. To identify
      problems the precheck-in tests would miss, continuous integration
      must also run a test suite more thorough than the precheck-in suite.
      In addition to being more thorough, these tests must run quickly
      enough so that a developer gets feedback while he still remembers
      what he was doing.

          One concern is that tests are difficult to write, particularly if
      you are working with an application that does not have a modular
      architecture. Don't let your concerns about not being able to do
      complete testing cause you to delay performing any testing. A simple
      test can tell you a lot about the health of your system. See the
      StickyNotes for some testing resources.

      To read more:  http://www.stickyminds.com/BetterSoftware/magazine.asp

      patricia powers williamson
      requirements   usability

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