Mocking External Services

Should your tests mock outside services or not? I keep seeing discussions on this topic. On the one hand, it lets your tests be in control of the testing context. Otherwise it may be very difficult to create a reliable automated test.

  • The external service might return different results at different times.
  • The external service might be slow to respond.
  • Using the external service might require running the test in a particular environment.
  • It may be impossible to generate certain error conditions with the real service.
  • There may be side-effects of using the real service.

On the other hand, our mock of the external service might differ from it in important ways.

  • Our mock service might have a slightly different interface than the real one.
  • Our mock service might accept slightly different parameters than the real one.
  • Our mock service might return slightly different results than the real one.
  • The real service might change behavior, and we won’t notice until we deploy to production.

This leaves us in a quandary. What to do? (Continued)

Changing Behavior by Asking the Right Questions

My article, Agile Adoption: Changing Behavior by Asking the Right Questions, has been published over on ProjectManagement.com (free registration required). It talks about when managers want change, but don’t want to squeeze the Agile out by force.

An open letter about unit tests

An open letter to a programmer who thinks that code coverage by integration tests eliminates the need for unit tests. (Continued)

Ways of expressing estimates

The way we express our estimates color both the way we think about the thing being estimated and the way our estimates are heard. (Continued)

Interchangeable Project Lenses Can Reveal the Unseen

If you look at things from the same point of view all the time, you’ll tend to see the same things, and overlook the same things. I discuss on ProjectManagement.com how to vary your view to get a better overall picture.

Pair Programming Lessons from Improv

Thanks to Tim Ottinger for reminding me of Arlo Belshee’s post, “Is Pair Programming for Me?” Go read Arlo’s post, as it’s insightful and has more useful content than most articles on pairing. I’m just going to springboard off of one skill that Arlo mentioned being important to learn.

How to avoid “paragraphing” when talking. Learning to speak in half-sentences, leaving room for the other to take the idea in an unexpected direction.

A few years back, I took a course in “Beginning Improv Acting.” (Continued)

Relationship of Cycle Time and Velocity

I sometimes see clashes between Kanban proponents and their Scrum counterparts. Despite the disagreements, both of these approaches tend toward the same goals and use many similar techniques. Karl Scotland and I did some root cause analysis of practices a few years back and came to the conclusion that there were a lot of similarities between Kanban and Scrum [as the poster-child of iterative agile] when viewed through that lens. I also noticed that while Scrum explicitly focuses on iterations as a control mechanism, Scrum teams tend get into trouble when they ignore Work In Progress (WIP). Conversely, while Kanban explicitly focuses on WIP, Kanban teams tend to get into trouble when they ignore Cadence.

A twitter conversation I was in revolved around Cycle Time and Velocity. Since this is a topic that’s come up before, I thought it would be valuable to describe it more fully. Again, I find there to be more similarities than differences between Kanban (which uses Cycle Time) and Scrum (which uses Velocity) in terms of predicting when a given amount of work will be done, or how much work will be done by a given time. (Continued)

Another Approach to the Diamond Kata

I saw that Alistair Cockburn had written a post about Seb Rose’s post on the Diamond Kata. I only read the beginning of both of those because I recognized the problem that Seb described with the “Gorilla” approach that, upon reaching the ‘C’ case.

“The code is now screaming for us to refactor it, but to keep all the tests passing most people try to solve the entire problem at once. That’s hard, because we’ll need to cope with multiple lines, varying indentation, and repeated characters with a varying number of spaces between them.”

I’ve run into such situations before, and it’s always be a clue for me to back up and work in smaller steps. Seb describes that the ‘B’ case, “easy enough to get this to pass by hardcoding the result.” Alistair describes the strategy as “shuffle around a bit” for the ‘B’ case. I’m not sure what “shuffling around a bit” means and I don’t think it would be particularly easy to get both ‘A’ and ‘B’ cases working with constants and not heading down a silly “if (letter == 'A') … elseif (letter == 'B') …” implementation. I was curious how I would approach it, and decided to try. (Ron Jeffries also wrote a post on the topic.) I didn’t read any of these three solutions before implementing my own, just so I could see what I would do. (Continued)

100 Top Agile Blogs

Luis Gonçalves has posted a list of 100 Top Agile Blogs, ranked by Alexa ranking. I’m gratified to make the list, where I’m in some pretty good company.

Another Two Sides to Estimation

There are many ways to look at the issue of estimation. Everyone in the business of software development has had experience with wanting estimates, being asked for estimates, or both. That experience frames how they look at the issue. A considerable share of those experiences have been painful. I dare say that everyone in the business has had some painful experiences around estimation, and the painful ones seem to stick in our memory more vividly than the benign ones.

What makes these experiences so painful? Again, the causes are legion. One frequent contributor is well illustrated by a story my older brother taught me as a child.

(Continued)