From 349c9f13c9bc6f7ae0e9fd1b64366f1f2ab42f12 Mon Sep 17 00:00:00 2001
From: Adam Becker <im.adam.becker@gmail.com>
Date: Sun, 7 Feb 2021 22:34:39 +0000
Subject: [PATCH] Add property args structure.

---
 src/Hedgehog/Hedgehog.fsproj |  1 +
 src/Hedgehog/Property.fs     | 53 +++++++++++++++++++++++-------------
 src/Hedgehog/PropertyArgs.fs | 16 +++++++++++
 src/Hedgehog/Report.fs       | 25 ++++++++++++++---
 4 files changed, 72 insertions(+), 23 deletions(-)
 create mode 100644 src/Hedgehog/PropertyArgs.fs

diff --git a/src/Hedgehog/Hedgehog.fsproj b/src/Hedgehog/Hedgehog.fsproj
index f5923a63..f94d0b79 100644
--- a/src/Hedgehog/Hedgehog.fsproj
+++ b/src/Hedgehog/Hedgehog.fsproj
@@ -41,6 +41,7 @@ https://github.com/hedgehogqa/fsharp-hedgehog/blob/master/doc/index.md
     <Compile Include="GenTuple.fs" />
     <Compile Include="Outcome.fs" />
     <Compile Include="Report.fs" />
+    <Compile Include="PropertyArgs.fs" />
     <Compile Include="PropertyConfig.fs" />
     <Compile Include="Property.fs" />
     <Compile Include="Linq\Gen.fs" />
diff --git a/src/Hedgehog/Property.fs b/src/Hedgehog/Property.fs
index c59bdfaf..dfa2550a 100644
--- a/src/Hedgehog/Property.fs
+++ b/src/Hedgehog/Property.fs
@@ -99,21 +99,19 @@ module Property =
     //
 
     let rec private takeSmallest
-            (renderRecheck : bool)
-            (size : Size)
-            (seed : Seed)
+            (args : PropertyArgs)
             (Node ((journal, x), xs) : Tree<Journal * Outcome<'a>>)
             (nshrinks : int<shrinks>)
             (shrinkLimit : int<shrinks> Option) : Status =
         let failed =
             Failed {
-                Size = size
-                Seed = seed
+                Size = args.Size
+                Seed = args.Seed
                 Shrinks = nshrinks
                 Journal = journal
-                RenderRecheck = renderRecheck
+                RecheckType = args.RecheckType
             }
-        let takeSmallest tree = takeSmallest renderRecheck size seed tree (nshrinks + 1<shrinks>) shrinkLimit
+        let takeSmallest tree = takeSmallest args tree (nshrinks + 1<shrinks>) shrinkLimit
         match x with
         | Failure ->
             match Seq.tryFind (Outcome.isFailure << snd << Tree.outcome) xs with
@@ -130,7 +128,7 @@ module Property =
         | Success _ ->
             OK
 
-    let private reportWith' (renderRecheck : bool) (size0 : Size) (seed : Seed) (config : PropertyConfig) (p : Property<unit>) : Report =
+    let private reportWith' (args : PropertyArgs) (config : PropertyConfig) (p : Property<unit>) : Report =
         let random = toGen p |> Gen.toRandom
 
         let nextSize size =
@@ -139,7 +137,7 @@ module Property =
             else
                 size + 1
 
-        let rec loop seed size tests discards =
+        let rec loop args tests discards =
             if tests = config.TestLimit then
                 { Tests = tests
                   Discards = discards
@@ -149,24 +147,29 @@ module Property =
                   Discards = discards
                   Status = GaveUp }
             else
-                let seed1, seed2 = Seed.split seed
-                let result = Random.run seed1 size random
+                let seed1, seed2 = Seed.split args.Seed
+                let result = Random.run seed1 args.Size random
+                let nextArgs = {
+                    args with
+                        Seed = seed2
+                        Size = nextSize args.Size
+                }
 
                 match snd (Tree.outcome result) with
                 | Failure ->
                     { Tests = tests + 1<tests>
                       Discards = discards
-                      Status = takeSmallest renderRecheck size seed result 0<shrinks> config.ShrinkLimit}
+                      Status = takeSmallest args result 0<shrinks> config.ShrinkLimit}
                 | Success () ->
-                    loop seed2 (nextSize size) (tests + 1<tests>) discards
+                    loop nextArgs (tests + 1<tests>) discards
                 | Discard ->
-                    loop seed2 (nextSize size) tests (discards + 1<discards>)
+                    loop nextArgs tests (discards + 1<discards>)
 
-        loop seed size0 0<tests> 0<discards>
+        loop args 0<tests> 0<discards>
 
     let reportWith (config : PropertyConfig) (p : Property<unit>) : Report =
-        let seed = Seed.random ()
-        p |> reportWith' true 1 seed config
+        let args = PropertyArgs.init
+        p |> reportWith' args config
 
     let report (p : Property<unit>) : Report =
         p |> reportWith PropertyConfig.defaultConfig
@@ -201,10 +204,22 @@ module Property =
         | _ -> failure
 
     let reportRecheckWith (size : Size) (seed : Seed) (config : PropertyConfig) (p : Property<unit>) : Report =
-        reportWith' false size seed config p
+        let args = {
+            PropertyArgs.init with
+                RecheckType = RecheckType.None
+                Seed = seed
+                Size = size
+        }
+        reportWith' args config p
 
     let reportRecheck (size : Size) (seed : Seed) (p : Property<unit>) : Report =
-        reportWith' false size seed PropertyConfig.defaultConfig p
+        let args = {
+            PropertyArgs.init with
+                RecheckType = RecheckType.None
+                Seed = seed
+                Size = size
+        }
+        reportWith' args PropertyConfig.defaultConfig p
 
     let reportRecheckBoolWith (size : Size) (seed : Seed) (config : PropertyConfig) (p : Property<bool>) : Report =
         p |> bind ofBool |> reportRecheckWith size seed config
diff --git a/src/Hedgehog/PropertyArgs.fs b/src/Hedgehog/PropertyArgs.fs
new file mode 100644
index 00000000..7a7867ac
--- /dev/null
+++ b/src/Hedgehog/PropertyArgs.fs
@@ -0,0 +1,16 @@
+namespace Hedgehog
+
+[<Struct>]
+type PropertyArgs = private {
+    RecheckType : RecheckType
+    Size : Size
+    Seed : Seed
+}
+
+module PropertyArgs =
+
+    let init = {
+        RecheckType = RecheckType.FSharp
+        Size = 0
+        Seed = Seed.random ()
+    }
diff --git a/src/Hedgehog/Report.fs b/src/Hedgehog/Report.fs
index 8ea85ab5..a551d898 100644
--- a/src/Hedgehog/Report.fs
+++ b/src/Hedgehog/Report.fs
@@ -4,12 +4,18 @@ namespace Hedgehog
 [<Measure>] type discards
 [<Measure>] type shrinks
 
+[<RequireQualifiedAccess>]
+type RecheckType =
+    | None
+    | CSharp
+    | FSharp
+
 type FailureData = {
     Size : Size
     Seed : Seed
     Shrinks : int<shrinks>
     Journal : Journal
-    RenderRecheck : bool
+    RecheckType : RecheckType
 }
 
 type Status =
@@ -80,14 +86,25 @@ module Report =
 
         Seq.iter (appendLine sb) (Journal.eval failure.Journal)
 
-        if failure.RenderRecheck then
+        match failure.RecheckType with
+        | RecheckType.None ->
+            ()
+
+        | RecheckType.FSharp ->
+            appendLinef sb "This failure can be reproduced by running:"
+            appendLinef sb "> Property.recheck %d ({ Value = %A; Gamma = %A }) <property>"
+                failure.Size
+                failure.Seed.Value
+                failure.Seed.Gamma
+
+        | RecheckType.CSharp ->
             appendLinef sb "This failure can be reproduced by running:"
-            appendLinef sb "> Property.recheck (%d : Size) ({ Value = %A; Gamma = %A }) <property>"
+            appendLinef sb "> property.Recheck(%d, new Seed { Value = %A; Gamma = %A })"
                 failure.Size
                 failure.Seed.Value
                 failure.Seed.Gamma
 
-        sb.ToString (0, sb.Length - 1) // Exclude extra newline.
+        sb.ToString().Trim() // Exclude extra newline.
 
     let render (report : Report) : string =
         match report.Status with