Add function Gen.timeSpan

src/Hedgehog/Gen.fs

@@ -512,6 +512,15 @@ module Gen =
             let! offsetMinutes = int32 (Range.linearFrom 0 (Operators.int minOffsetMinutes) (Operators.int maxOffsetMinutes))
             return DateTimeOffset(ticks, TimeSpan.FromMinutes (Operators.float offsetMinutes))
         }
+
+#if !FABLE_COMPILER
+    /// Generates a random TimeSpan using the specified range.
+    let timeSpan (range : Range<TimeSpan>) : Gen<TimeSpan> =
+        range
+        |> Range.map (fun x -> x.Ticks (* Fable can't do this *))
+        |> int64
+        |> map TimeSpan.FromTicks
+#endif
 
     //
     // Sampling

tests/Hedgehog.Tests/GenTests.fs

@@ -64,6 +64,23 @@ let genTests = testList "Gen tests" [
         |> List.distinct
         |> List.length
         =! actual.Length
+
+#if !FABLE_COMPILER
+// See production code
+    yield! testCases "timeSpan creates TimeSpan instances"
+        [ 8; 16; 32; 64; 128; 256; 512 ] <| fun count ->
+
+        let actual =
+            (Range.constant TimeSpan.MinValue TimeSpan.MaxValue)
+            |> Gen.timeSpan
+            |> Gen.sample 0 count
+            |> Seq.toList
+
+        actual
+        |> List.distinct
+        |> List.length
+        =! actual.Length
+#endif
 
     testCase "unicode does not return any surrogate" <| fun _ ->
         let actual =