Add cats Eq/Order for Quantity

.gitignore

@@ -11,6 +11,7 @@ lib_managed/
 src_managed/
 project/boot/
 project/plugins/project/
+project/metals.sbt
 
 # Scala-IDE specific
 .scala_dependencies

.travis.yml

@@ -25,4 +25,4 @@ before_cache:
 script:
   - sbt ++${TRAVIS_SCALA_VERSION} clean &&
     sbt ++${TRAVIS_SCALA_VERSION} compile &&
-    sbt ++${TRAVIS_SCALA_VERSION} coulomb_tests/test
+    sbt ++${TRAVIS_SCALA_VERSION} coulomb_tests/test coulomb_testkit/test

build.sbt

@@ -1,6 +1,8 @@
 // xsbt clean unidoc previewSite
 // xsbt clean unidoc ghpagesPushSite
 
+Global / onChangedBuildSource := ReloadOnSourceChanges
+
 def commonSettings = Seq(
   organization := "com.manyangled",
   version := "0.4.7-SNAPSHOT",
@@ -120,6 +122,32 @@ def coulombPureConfigDeps = Seq(
   "com.github.pureconfig" %% "pureconfig-generic" % "0.13.0" % Provided,
 )
 
+def coulombCatsDeps = Seq(
+  "org.typelevel" %% "cats-core" % "2.1.1" % Provided
+)
+
+lazy val coulomb_cats = (project in file("coulomb-cats"))
+  .aggregate(coulomb)
+  .dependsOn(coulomb)
+  .settings(name := "coulomb-cats")
+  .settings(commonSettings :_*)
+  .settings(docDepSettings :_*)
+  .settings(libraryDependencies ++= coulombCatsDeps)
+
+def coulombTestkitDeps = Seq(
+   "org.typelevel" %% "cats-testkit" % "2.1.1" % Provided,
+   "org.typelevel" %% "cats-testkit-scalatest" % "1.0.1" % Provided
+)
+
+lazy val coulomb_testkit = (project in file("coulomb-testkit"))
+  .aggregate(coulomb, coulomb_si_units, coulomb_cats)
+  .dependsOn(coulomb, coulomb_si_units, coulomb_cats)
+  .settings(name := "coulomb-testkit")
+  .settings(commonSettings :_*)
+  .settings(docDepSettings :_*)
+  .settings(libraryDependencies ++= coulombCatsDeps)
+  .settings(libraryDependencies ++= coulombTestkitDeps)
+
 lazy val coulomb_pureconfig = (project in file("coulomb-pureconfig"))
   .aggregate(coulomb, coulomb_parser)
   .dependsOn(coulomb, coulomb_parser)
@@ -150,8 +178,8 @@ lazy val coulomb_pureconfig_refined = (project in file("coulomb-pureconfig-refin
   .settings(libraryDependencies ++= coulombRefinedDeps)
 
 lazy val coulomb_tests = (project in file("coulomb-tests"))
-  .aggregate(coulomb, coulomb_si_units, coulomb_mks_units, coulomb_accepted_units, coulomb_time_units, coulomb_info_units, coulomb_customary_units, coulomb_temp_units, coulomb_parser, coulomb_typesafe_config, coulomb_avro, coulomb_pureconfig, coulomb_refined, coulomb_pureconfig_refined)
-  .dependsOn(coulomb, coulomb_si_units, coulomb_mks_units, coulomb_accepted_units, coulomb_time_units, coulomb_info_units, coulomb_customary_units, coulomb_temp_units, coulomb_parser, coulomb_typesafe_config, coulomb_avro, coulomb_pureconfig, coulomb_refined, coulomb_pureconfig_refined)
+  .aggregate(coulomb, coulomb_si_units, coulomb_mks_units, coulomb_accepted_units, coulomb_time_units, coulomb_info_units, coulomb_customary_units, coulomb_temp_units, coulomb_parser, coulomb_typesafe_config, coulomb_avro, coulomb_pureconfig, coulomb_refined, coulomb_pureconfig_refined, coulomb_cats, coulomb_testkit)
+  .dependsOn(coulomb, coulomb_si_units, coulomb_mks_units, coulomb_accepted_units, coulomb_time_units, coulomb_info_units, coulomb_customary_units, coulomb_temp_units, coulomb_parser, coulomb_typesafe_config, coulomb_avro, coulomb_pureconfig, coulomb_refined, coulomb_pureconfig_refined, coulomb_cats, coulomb_testkit)
   .settings(name := "coulomb-tests")
   .settings(commonSettings :_*)
   .settings(libraryDependencies ++= coulombParserDeps)

coulomb-cats/src/main/scala/coulomb/cats/package.scala

@@ -0,0 +1,24 @@
+package coulomb.cats
+
+import cats._
+import cats.implicits._
+import coulomb.Quantity
+
+trait CatsImplicits {
+  /**
+    * Eq[Quantity[A, B]] when there is an Eq[A]
+    *
+    * @group typeclass
+    */
+  implicit def eqQuantity[A: Eq, B]: Eq[Quantity[A, B]] = Eq.by(_.value)
+
+  /**
+    * Order[Quantity[A, B]] when there is an Order[A]
+    *
+    * @group typeclass
+    */
+  implicit def orderQuantity[A: Order, B]: Order[Quantity[A, B]] = Order.by(_.value)
+
+}
+
+object implicits extends CatsImplicits

coulomb-testkit/src/main/scala/coulomb/arb/ArbQuantity.scala

@@ -0,0 +1,19 @@
+package coulomb.arb
+
+import org.scalacheck.Arbitrary
+import org.scalacheck.Arbitrary._
+import org.scalacheck.Cogen
+import coulomb._
+
+trait ArbQuantity {
+  implicit def arbQuantity[A: Arbitrary, B]: Arbitrary[Quantity[A, B]] = Arbitrary {
+    for {
+      a <- arbitrary[A]
+    } yield Quantity(a)
+  }
+
+  implicit def arbCogen[A: Cogen, B]: Cogen[Quantity[A, B]] =
+    Cogen[A].contramap(_.value)
+}
+
+object ArbQuantity extends ArbQuantity

coulomb-testkit/src/test/scala/coulomb/cats/CatsSpec.scala

@@ -0,0 +1,18 @@
+package coulomb.cats
+
+import cats.tests.CatsSuite
+import cats.{ Eq, Show, Order }
+import cats.kernel.laws.discipline._
+import coulomb._
+import coulomb.cats.implicits._
+import coulomb.si._
+import coulomb.siprefix._
+
+final class CatsSpec extends CatsSuite {
+  import coulomb.arb.ArbQuantity._
+
+  type Units = (Kilo %* Meter) %/ Second
+
+  checkAll("EqTest", EqTests[Quantity[Int, Units]].eqv)
+  checkAll("OrderTest", OrderTests[Quantity[Int, Units]].order)
+}