Integration testing and unit testing

Also known as, “An exercise in Twitter opinionating”:

Sitting in a meeting, I heard one of the other meeting participants say, “You should do your integration testing before your unit testing in your code.”

Now, I wasn’t (and I’m still not) sure I agree with this or not, and when in doubt, I like to get data points. Twitter to the rescue!

The responses that came back were fascinating, and all over the map:

MarkFreedman

Why? Disagree, unless I'm missing something => RT @tedneward: OH: "You should do your integration testing before your unit testing."

kiranhatti

@tedneward disagree! How could an unstable code (not unit tested)be ready for integration testing

bradwilson

@tedneward Write acceptance tests, so we're all on the same page, then use TDD to get components in place until acceptance tests pass.

bradwilson

@tedneward There is value on an agile team for starting with automated acceptance tests, as a stopping function for development effort.

iceX33

@tedneward mostly agree integration first helps to focus on feature, not losing in details

JasonBarile

@tedneward Depends on the intent of the integration testing. If it's to find gaps in the feature set, maybe. Otherwise, disagree.

justncase80

@tedneward disagree. The order depends on what you're creating.

RockyLhotka

@tedneward I continually intermix them; can't say I care a lot about the distinction either in most cases

secos

@tedneward in the sense that you may want to have some of the integration work done before you write the internals, yes.

My next thought was “how do I capture this for further discussion”, so here we go.

Couple of thoughts that occur to me as I read through the responses:

• Are acceptance tests the same as integration tests?
• Are either of these at the same level of scope as unit tests?
• Does it make a difference which order you approach them?

Love to hear your thoughts.