undefined Link classNames after upgrading 2.0 -> 2.2

[sprzybylski]

My tests started to fail after upgrading to 2.2, what was unexpected bumping just minor version.
I was expecting every Link component to have className props.

Should we update upgrade guide for 2.2 or this should be considered a bug?

const links = TestUtils.scryRenderedComponentsWithType(component, Link);
links.map((link) => link.props.className)

2.0.1 outputs:
[ '', 'a-class-name' ]
2.2.2 outputs:
[ undefined, 'a-class-name' ]

[ryanflorence]

Sorry it broke your tests. Rendering w/ empty classNames was a bug so we don't consider it a breaking change.

We could add a note in the upgrade guide that tests that are that specific may break.

#3288

[sprzybylski]

Thanks!
Want me to make a PR with the note?
Below part of test case for my pagination component that failed after upgrading.

const links = TestUtils.scryRenderedComponentsWithType(component, Link);
const previous = links.find((link) => link.props.className.match('previous'));
previous.props.to.should.equal(correctPath);

[taion]

@sprzybylski That's a generally not-recommended pattern for testing classes. You should be asserting on the actual rendered classes, not props.className.