From 936401370d1af3d74e70c3d68a1b1a626bfa40ca Mon Sep 17 00:00:00 2001
From: Andy Scott <andy.g.scott@gmail.com>
Date: Mon, 30 Oct 2017 15:50:10 -0700
Subject: [PATCH] Add Validated.cond and Validated.condNel

---
 core/src/main/scala/cats/data/Validated.scala      | 14 ++++++++++++++
 .../src/test/scala/cats/tests/ValidatedSuite.scala | 12 ++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/core/src/main/scala/cats/data/Validated.scala b/core/src/main/scala/cats/data/Validated.scala
index e0b000e8d0..4cc8d56884 100644
--- a/core/src/main/scala/cats/data/Validated.scala
+++ b/core/src/main/scala/cats/data/Validated.scala
@@ -587,4 +587,18 @@ private[data] trait ValidatedFunctions {
     * Converts an `Ior[A, B]` to a `Validated[A, B]`.
     */
   def fromIor[A, B](ior: Ior[A, B]): Validated[A, B] = ior.fold(invalid, valid, (_, b) => valid(b))
+
+  /**
+   * If the condition is satisfied, return the given `B` as valid,
+   * otherwise return the given `A` as invalid.
+   */
+  final def cond[A, B](test: Boolean, b: => B, a: => A): Validated[A, B] =
+    if (test) valid(b) else invalid(a)
+
+  /**
+   * If the condition is satisfied, return the given `B` as valid NEL,
+   * otherwise return the given `A` as invalid NEL.
+   */
+  final def condNel[A, B](test: Boolean, b: => B, a: => A): ValidatedNel[A, B] =
+    if (test) validNel(b) else invalidNel(a)
 }
diff --git a/tests/src/test/scala/cats/tests/ValidatedSuite.scala b/tests/src/test/scala/cats/tests/ValidatedSuite.scala
index c52720f4c5..137311a05f 100644
--- a/tests/src/test/scala/cats/tests/ValidatedSuite.scala
+++ b/tests/src/test/scala/cats/tests/ValidatedSuite.scala
@@ -267,4 +267,16 @@ class ValidatedSuite extends CatsSuite {
       }
     }
   }
+
+  test("cond consistent with Either.cond + toValidated") {
+    forAll { (cond: Boolean, s: String, i: Int) =>
+      Validated.cond(cond, s, i) should === (Either.cond(cond, s, i).toValidated)
+    }
+  }
+
+  test("condNel consistent with Either.cond + toValidatedNel") {
+    forAll { (cond: Boolean, s: String, i: Int) =>
+      Validated.condNel(cond, s, i) should === (Either.cond(cond, s, i).toValidatedNel)
+    }
+  }
 }