Add platform specific instances

Author: ghostbuster91

core/src/main/scala/com/softwaremill/diffx/Diff.scala

@@ -29,7 +29,7 @@ trait Diff[-T] { outer =>
     }
 }
 
-object Diff extends MiddlePriorityDiff with TupleInstances {
+object Diff extends MiddlePriorityDiff with TupleInstances with DiffxPlatformExtensions {
   def apply[T: Diff]: Diff[T] = implicitly[Diff[T]]
 
   def ignored[T]: Diff[T] = (_: T, _: T, _: DiffContext) => DiffResult.Ignored

core/src/main/scalajs/diffx/DiffxPlatformExtensions.scala

@@ -0,0 +1,3 @@
+package com.softwaremill.diffx
+
+trait DiffxPlatformExtensions

core/src/main/scalajvm/com/softwaremill/diffx/DiffxPlatformExtensions.scala

@@ -0,0 +1,15 @@
+package com.softwaremill.diffx
+
+import java.time._
+import java.util.UUID
+
+trait DiffxPlatformExtensions {
+  implicit val diffUuid: Diff[UUID] = Diff.fallback
+
+  implicit val diffInstant: Diff[Instant] = Diff.fallback
+  implicit val diffLocalDate: Diff[LocalDate] = Diff.fallback
+  implicit val diffLocalTime: Diff[LocalTime] = Diff.fallback
+  implicit val diffLocalDateTime: Diff[LocalDateTime] = Diff.fallback
+  implicit val diffOffsetDateTime: Diff[OffsetDateTime] = Diff.fallback
+  implicit val diffZonedDateTime: Diff[ZonedDateTime] = Diff.fallback
+}

core/src/test/scalajvm/com/softwaremill/diffx/test/DiffxJvmInstancesTest.scala

@@ -0,0 +1,37 @@
+package com.softwaremill.diffx.test
+
+import com.softwaremill.diffx.{Diff, DiffResult}
+import org.scalatest.freespec.AnyFreeSpec
+import org.scalatest.matchers.should.Matchers
+
+import java.time._
+import java.util.UUID
+
+class DiffxJvmInstancesTest extends AnyFreeSpec with Matchers {
+  val cases = List(
+    TestCase("LocalDate", LocalDate.now(), LocalDate.now().plusDays(1)),
+    TestCase("LocalTime", LocalTime.now(), LocalTime.now().plusHours(1)),
+    TestCase("LocalDateTime", LocalDateTime.now(), LocalDateTime.now().plusDays(1)),
+    TestCase("OffsetDateTime", OffsetDateTime.now(), OffsetDateTime.now().plusDays(1)),
+    TestCase("ZonedDateTime", ZonedDateTime.now(), ZonedDateTime.now().plusDays(1)),
+    TestCase("Instant", Instant.now(), Instant.now().plusMillis(100)),
+    TestCase("UUID", UUID.randomUUID(), UUID.randomUUID())
+  )
+
+  cases.foreach { tc =>
+    tc.clazz - {
+      s"identical ${tc.clazz}s should be identical" in {
+        tc.compareIdentical.isIdentical shouldBe true
+      }
+
+      s"different ${tc.clazz}s should be different" in {
+        tc.compareDifferent.isIdentical shouldBe false
+      }
+    }
+  }
+
+  case class TestCase[T: Diff](clazz: String, v1: T, v2: T) {
+    def compareIdentical: DiffResult = Diff.compare(v1, v1)
+    def compareDifferent: DiffResult = Diff.compare(v1, v2)
+  }
+}