Save the code or save the tests? @ Things Of Interest
Your data centre is on fire, and all your application code is on one drive, and all your tests are on the other drive, and you can only rescue one. What do you do?
More recently, out of curiosity, I pitched the same question as a poll on Twitter. On Twitter, roughly 80% of respondents said that they would save the application code and 20% said they would save the tests.
People gave differing reasons for their decisions. Predictably, many respondents said to let it all burn, and some people attempted to justify that choice by asserting that they had backups. But "let it all burn" wasn't one of the provided options and these responses didn't show up in the results, so we can safely ignore those opinions for now.
Most of the remaining respondents seemed to make decisions based on their own assumptions about how detailed and specific those tests actually were. Some people said that it was impossible to make the decision without knowing more about the tests. Some people said to save the application code because the other drive, containing their tests, would be blank, or at least contain nothing of value. Some people said they would save the application code because although the tests might exist, and even be quite robust, they would not specify enough of the application's behaviours to make recreating the application possible. Some added that they would try to rebuild the tests from the saved application codebase. This, of course, also involves significant assumptions about the testability of the application.
But some people, of course, asserted that their tests would be exhaustive enough that rebuilding the application from the test code would be easier.
