Add missing tests for Either syntax

tests/src/test/scala/cats/tests/EitherTests.scala

@@ -255,4 +255,29 @@ class EitherTests extends CatsSuite {
  x.to[Option] should === (x.toOption)
  }
  }
+
+ test("partialCompare consistent with PartialOrder") {
+ forAll { (x: Either[Int, String], y: Either[Int, String]) =>
+ x.partialCompare(y) should === (partialOrder.partialCompare(x, y))
+ }
+ }
+
+ test("show Right") {
+ val either = Either.right[String, Int](10)
+ either.show should === ("Right(10)")
+ }
+
+ test("show Left") {
+ val either = Either.left[String, Int]("string")
+ either.show should === ("Left(string)")
+ }
+
+ test("ap consistent with Applicative") {
+ val fab = implicitly[Applicative[Either[String, ?]]]
+ forAll { (fa: Either[String, Int],
+ f: Int => String) =>
+ fa.ap(Either.right(f)) should === (fab.map(fa)(f))
+ }
+ }
+
 }