Pretty diffs for case classes.

To use with scalatest, add the following dependency:

"com.softwaremill.diffx" %% "diffx-scalatest" % "0.2.0"

Then, extend the com.softwaremill.diffx.scalatest.DiffMatcher trait or import com.softwaremill.diffx.scalatest.DiffMatcher._. After that you will be able to use syntax such as:

left should matchTo(right)

Giving you nice error messages:

Add the following dependency:

"com.softwaremill.diffx" %% "diffx-core" % "0.2.0"

Then call:

import com.softwaremill.diffx.Diff
Diff[T].diff(o1, o2)

If you'd like to implement custom matching logic for given type, create an implicit Diff instance for that type, and make sure it's in scope when creating Diff for the root type.

Fields can be excluded from comparision simply by calling ignore method on Diff instance. Since Diff instances are immutable it creates a copy with modified logic. You can use this instance explicitly. If you still would like to use it implicitly you first need to summon instance of Diff typeclass using Derived typeclass wrapper: Derived[Diff[Person]]. Thanks to that trick latter you will be able to put your modified instance of Diff typeclass into implicit scope. The whole process looks following:

implicit modifiedDiff: Diff[Person] = Derived[Diff[Person]].ignore(_.name)