Blog logotrial and stderr


A 3 post collection

Choose unique names for test fixtures

 •  Filed under testing, art

In a library I maintain, I wrote all the tests using names from the foo-bar-baz family in fixtures.

I realized that having 50 tests where all the test data is foo-bar-baz makes it harder to debug. Adding a console.log to a line that gets hit 50 times might yield variations on { foo: "bar" } for all 50 tests, but only one corresponds to the error I'm interested.

That's why I've switched to pulling random names from a less limited domain. For this library, I'm using Japanese food names. It doesn't matter what they are or what they mean. What matters is that I can search my test logs for tamago and, if I've only used tamago in one test, immediately find the data corresonding to the test I'm interested in, { tamago: { kake: "gohan" } }. Delicious.

Factoring out and bad abstractions

 •  Filed under art

Something or other has lead me to reading a lot about bad abstractions lately, including a famous article where Sandi Metz writes

duplication is far cheaper than the wrong abstraction

I want to add that it's not just a matter of choosing between two cognizable options. It's that all programmers chronically underestimate the difficulty of inventing new abstractions. We need to take that into account in deciding whether to take the leap in the first place.

I want to reframe the idea of "factoring out common code" and "avoiding copy-pasting." Every time you do one of these simple-sounding things, you are actually inventing an abstraction. You are engaging in the most intellectually demanding act of software engineering. It involves balancing the predicted cognitive load which exists outside, via, and inside your abstraction. It requires you to predict the future about business requirements and code that is yet to be written. On top of all that, it is a test of your mastery of technical jargon, of grammatical norms in programming, and of the English language itself.

Naming has been compared in difficulty to cache invalidation, and yet I don't seem to be surrounded by half-baked attempts at cache implementations.

When Kent C. Dodds says to Avoid Hasty Abstractions, remember that he is a famous expert programmer. "Not hasty" for him sets a pretty high bar for you and me.