Comments on: Book Club: An agile approach to a legacy system (Chris Stevenson and Andy Pols) http://www.markhneedham.com/blog/2009/07/15/book-club-an-agile-approach-to-a-legacy-system-chris-stevenson-and-andy-pols/ Thoughts on Software Development Thu, 18 Mar 2010 23:29:00 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: Mark Needham http://www.markhneedham.com/blog/2009/07/15/book-club-an-agile-approach-to-a-legacy-system-chris-stevenson-and-andy-pols/comment-page-1/#comment-29730 Mark Needham Mon, 04 Jan 2010 11:32:01 +0000 http://www.markhneedham.com/blog/?p=1458#comment-29730 Hi Andy, Cool that makes sense - thanks for clarifying. Really interesting paper though, we enjoyed reading it. Hi Andy,

Cool that makes sense – thanks for clarifying.

Really interesting paper though, we enjoyed reading it.

]]> By: Andy Pols http://www.markhneedham.com/blog/2009/07/15/book-club-an-agile-approach-to-a-legacy-system-chris-stevenson-and-andy-pols/comment-page-1/#comment-29728 Andy Pols Mon, 04 Jan 2010 11:23:49 +0000 http://www.markhneedham.com/blog/?p=1458#comment-29728 Hi Mark, thanks for reading our paper! To try and answer your question about why the rewrite was just writing legacy code (even though the rewrite had lots of tests): Due to the nature of the stored procedures (possibly triggered by external events unknown to us at the time - the parallel running was a voyage of discovery) it was difficult to specify the correct behaviour in a test. Just because it did something today did not imply the same was true tomorrow. So we did not have the usual test safety net. It was also taking a huge amount of time and energy and not delivering anything new (the business already had the same functionality in the original system) Hope that makes sense? Hi Mark, thanks for reading our paper! To try and answer your question about why the rewrite was just writing legacy code (even though the rewrite had lots of tests):

Due to the nature of the stored procedures (possibly triggered by external events unknown to us at the time – the parallel running was a voyage of discovery) it was difficult to specify the correct behaviour in a test. Just because it did something today did not imply the same was true tomorrow. So we did not have the usual test safety net.

It was also taking a huge amount of time and energy and not delivering anything new (the business already had the same functionality in the original system)

Hope that makes sense?

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