Added more seeding methods

doc/changelog/0.7.3.md

@@ -3,7 +3,10 @@
 * Added to `object Gen`:
   * `uuid` for UUIDs.
   * `randomSeed` to generate and apply a random (non-determinstic) seed.
-  *
+  * `setOptionalSeed`.
 
 * Added to `Gen` instances:
   * `>>` to discard the result and `flatMap` to something else.
+  * `withSeed`.
+  * `withOptionalSeed`.
+  * `withRandomSeed`.

nyaya-gen/src/main/scala/nyaya/gen/Gen.scala

@@ -63,6 +63,15 @@ final case class Gen[+A](run: Gen.Run[A]) extends AnyVal {
     // This is what scala.Future does
       throw new NoSuchElementException("Gen.withFilter predicate is not satisfied"))
 
+  def withSeed(seed: Long): Gen[A] =
+    Gen.setSeed(seed) >> this
+
+  def withOptionalSeed(s: Option[Long]): Gen[A] =
+    Gen.setOptionalSeed(s) >> this
+
+  def withRandomSeed: Gen[A] =
+    Gen.randomSeed >> this
+
   def option: Gen[Option[A]] =
     Gen(c => if (c.nextBit()) None else Some(run(c)))
 
@@ -392,6 +401,9 @@ object Gen {
   def setSeed(seed: Long): Gen[Unit] =
     Gen(_ setSeed seed)
 
+  def setOptionalSeed(s: Option[Long]): Gen[Unit] =
+    s.fold(unit)(setSeed)
+
   /**
    * Apply a new deterministic seed to the RNG.
    *

nyaya-test/src/test/scala/nyaya/gen/GenTest.scala

@@ -200,5 +200,19 @@ object GenTest extends TestSuite {
       assert(a != b)
     }
 
+    'withSeed {
+      val (a,b,c,d,e) = Gen.tuple5(
+        Gen.long,
+        Gen.long,
+        Gen.long withSeed 0,
+        Gen.long withSeed 1,
+        Gen.long).sample()
+      val s0 = -4962768465676381896L
+      val s1 = -4964420948893066024L
+      val n1 = 7564655870752979346L
+      assert(c == s0, d == s1, e == n1)
+      assert(Set(a,b,c,d,e).size == 5)
+    }
+
   }
 }