Add scalafix rule for renaming assert to expect

[zainab-ali]

This is a follow up to #69 . The RenameAssertToExpect rule renames calls to weaver assert to expect.

As part of the release, it would be great to add upgrade notes to the documentation and a scalafix migration.

[Baccata]

I'm not fully versed in scalafix migrations, but considering none of this code is wired in the sbt-build, does it mean that the scalafix folder is meant to be a self-contained project and scala-steward is able to build it on the fly ?

[kubukoz]

Are we missing the definition of RenameAssertToExpect?

[kubukoz]

Can you explain the need for the custom TargetAxis please? (also I suppose it has something to do with why this is mixing 2.12 and 3.x)

[zainab-ali]

Apologies - I missed out a lot of context.

The scalafix directory is completely separate from the weaver build. It's intended to be temporary: we can delete this directory as soon as the assert / expect change is released.

A lot of the files (build.sbt and TargetAxis) were created by the scalafix Giter8 template. They let us run local tests against different Scala versions with sbt tests/test.

Since we don't need to maintain them past the release, I haven't looked into them in detail.

Scala steward migrations

The rule will be run by Scala steward, provided we add some config to the Scala steward repo.

The only necessary file for scala steward (or our users) to run the rule is the RenameAssertToExpect.scala file.

You can try this out locally on any project with the sbt-scalafix plugin:

sbt scalafixAll github:zainab-ali/typelevel-weaver-test/RenameAssertToExpect?sha=assert-scalafix-rule

The release process

When we instruct scala steward (or our users) to apply the rule, we'll reference a specific tag.

For example, if this rule is meant to be run as part of a v1.0.0 release, we can tell users to run:

sbt scalafixAll github:typelevel/weaver-test/RenameAssertToExpect?sha=v1.0.0

Since the file is referenced through a tag, we can delete the scalafix directory after the v1.0.0 release.

On a related note, I'm looking into how we can use scala steward's artifact migrations to seamlessly migrate users from disney to typelevel. Scala steward would need to migrate the artifact and apply the RenameAssertToExpect rule in one go.

I don't think there are any other API changes we can mitigate through scalafix rules. We have changed the signature of expect.same, but this should be source compatible for most users.