What's the difference between .feature and .specb, and which should I use?

[dmytro-stasyuk]

I see both .feature and .specb used across the docs and examples.

Is there any difference in how SpecBinder treats them, and is there a reason to pick one over the other?

[dmytro-stasyuk]

Either one works. Nothing about how SpecBinder reads your spec or generates your tests changes
between them, and you can switch later by renaming the file.

.specb is SpecBinder's own extension, and the one used throughout these docs and examples.
Nothing else claims it, so a .specb file is unambiguously a SpecBinder spec — which is what
keeps it out of the way of other tools.

That shows up most clearly in IntelliJ. SpecBinder has a companion IntelliJ plugin (optional —
your tests are generated with or without it) that adds editor support for spec files: clicking
through from a step to the code behind it, run buttons in the left margin, pass/fail marks after
a run. The Cucumber/Gherkin plugin does that same job for .feature files. If both are installed, each
wants to own .feature files and only one can. A .specb file never enters that contest.

Telling SpecBinder which files to read

You point SpecBinder at your spec files with a @Gherkin2JUnit annotation on a class. There are
two ways to do that, and the extension only matters for one of them:

• Give an exact path — @Gherkin2JUnit("specs/cart.specb") — and the extension is ignored.
  That file is read whatever it's called.
• Let SpecBinder find the files for you — @Gherkin2JUnit with nothing in the brackets picks
  up the spec files sitting beside the class. Here only files whose extension SpecBinder
  recognises as a spec are picked up. Out of the box that means both .specb and .feature, so
  either is found without you configuring anything.

To change which extensions SpecBinder recognises, add a second annotation beside the first and
write them without their dots:

@Gherkin2JUnit
@Gherkin2JUnitOptions(supportedFileExtensions = {"feature", "specb"})  // already the default
public abstract class ShoppingCartFeature { }

In IntelliJ

The SpecBinder plugin has its own separate setting for which files it gives editor support to:
Settings → Tools → SpecBinder → File extensions, where you can pick both, only .feature,
or only .specb. That's independent of which files SpecBinder reads when it generates your tests.