Fix unusable replay seed with FsCheck3 (#501)

* Fix unusable replay seed with FsCheck3

* Documentation for replay seed type change

* Test for replay seed backward compatibility

* Remove unused import

Expecto.FsCheck/FsCheck.fs

@@ -71,7 +71,7 @@ module ExpectoFsCheck =
                           (String.concat " " data.Labels)
 
               let focus =
-                sprintf "Focus on error:\n\t%s (%i, %i) \"%s\"" methodName std gen name
+                sprintf "Focus on error:\n\t%s (%A, %A) \"%s\"" methodName (uint64 std) (uint64 gen) name
 
               sprintf "Failed after %s. %s%s\nResult:\n\t%A\n%s%s%s"
                       (numTests data.NumberOfTests) parameters shrunk
@@ -90,7 +90,9 @@ module ExpectoFsCheck =
       let config =
         { MaxTest = config.maxTest
           MaxFail = 1000
-          Replay = Option.map Random.StdGen config.replay
+          // We're converting uint64s to a smaller type, but it shouldn't be an issue because users are only using the
+          // values given in the test output, which are only ints when running FsCheck 2
+          Replay = Option.map Random.StdGen (config.replay |> Option.map (fun (seed, gamma) -> int seed, int gamma))
           Name = name
           StartSize = config.startSize
           EndSize = config.endSize

Expecto.FsCheck3/FsCheck3.fs

@@ -71,7 +71,7 @@ module ExpectoFsCheck =
                           (String.concat " " data.Labels)
 
               let focus =
-                sprintf "Focus on error:\n\t%s (%i, %i) \"%s\"" methodName originalSeed.Seed originalSeed.Gamma name
+                sprintf "Focus on error:\n\t%s (%A, %A) \"%s\"" methodName originalSeed.Seed originalSeed.Gamma name
 
               sprintf "Failed after %s. %s%s\nResult:\n\t%A\n%s%s%s"
                       (numTests data.NumberOfTests) parameters shrunk
@@ -91,7 +91,7 @@ module ExpectoFsCheck =
       let config =
         Config.Default
             .WithMaxTest(config.maxTest)
-            .WithReplay(Option.map (fun (seed,gamma) -> {Rnd = Rnd(uint64 seed, uint64 gamma); Size = None}) config.replay)
+            .WithReplay(Option.map (fun (seed,gamma) -> {Rnd = Rnd(seed, gamma); Size = None}) config.replay)
             .WithName(name)
             .WithStartSize(config.startSize)
             .WithEndSize(config.endSize)

Expecto.Tests.FsCheck3/FsCheck3Tests.fs

@@ -60,7 +60,7 @@ let focused =
   testList "FsCheck focused" [
     testCase "ignore me" <| ignore
 
-    etestProperty (1,3) "Deliberately failing test" <|
+    etestProperty (1UL,3UL) "Deliberately failing test" <|
       fun a b c ->
         // wrong on purpose to test failures
         a * (b + c) = a * a + a * c
@@ -94,7 +94,7 @@ Shrunk 2 times to:
 Result:
 	Failed System.Exception: Expected true, got false.
 Focus on error:
-	etestProperty (1, 3) \"Deliberately failing test\""
+	etestProperty (1UL, 3UL) \"Deliberately failing test\""
       Expect.equal actual expected "It should fail with the right message"
     | x ->
       failtestf "Expected Failed, actual was: %A" x
@@ -104,7 +104,7 @@ let config =
   testList "FsCheck config" [
     testCase "ignore me" ignore
 
-    etestPropertyWithConfig (1,3) FsCheckConfig.defaultConfig
+    etestPropertyWithConfig (1UL,3UL) FsCheckConfig.defaultConfig
       "Deliberately failing test" <|
       fun a b c ->
         // wrong on purpose to test failures
@@ -139,9 +139,13 @@ Shrunk 2 times to:
 Result:
 	Failed System.Exception: Expected true, got false.
 Focus on error:
-	etestPropertyWithConfig (1, 3) \"Deliberately failing test\""
+	etestPropertyWithConfig (1UL, 3UL) \"Deliberately failing test\""
       Expect.equal actual expected "It should fail with the right message."
 
     | x ->
       failtestf "Expected Failed, actual %A" x
-  }
+  }
+
+[<Tests>]
+let runFsCheckReplaySeedMigrationTests =
+  testProperty "int32/uint64 roundtrip" <| fun (FsCheck.DoNotSize(n)) -> n = int32 (uint64 n)

Expecto.Tests/FsCheckTests.fs

@@ -60,7 +60,7 @@ let focused =
   testList "FsCheck focused" [
     testCase "ignore me" <| ignore
 
-    etestProperty (1,2) "Deliberately failing test" <|
+    etestProperty (1UL,2UL) "Deliberately failing test" <|
       fun a b c ->
         // wrong on purpose to test failures
         a * (b + c) = a * a + a * c
@@ -94,7 +94,7 @@ Shrunk 4 times to:
 Result:
 	False
 Focus on error:
-	etestProperty (1, 2) \"Deliberately failing test\""
+	etestProperty (1UL, 2UL) \"Deliberately failing test\""
       Expect.equal actual expected "It should fail with the right message"
     | x ->
       failtestf "Expected Failed, actual was: %A" x
@@ -104,7 +104,7 @@ let config =
   testList "FsCheck config" [
     testCase "ignore me" ignore
 
-    etestPropertyWithConfig (1,2) FsCheckConfig.defaultConfig
+    etestPropertyWithConfig (1UL,2UL) FsCheckConfig.defaultConfig
       "Deliberately failing test" <|
       fun a b c ->
         // wrong on purpose to test failures
@@ -139,7 +139,7 @@ Shrunk 4 times to:
 Result:
 	False
 Focus on error:
-	etestPropertyWithConfig (1, 2) \"Deliberately failing test\""
+	etestPropertyWithConfig (1UL, 2UL) \"Deliberately failing test\""
       Expect.equal actual expected "It should fail with the right message."
 
     | x ->

Expecto/Model.fs

@@ -16,7 +16,7 @@ type FsCheckConfig =
     /// The size to use for the last test, when all the tests are passing. The size increases linearly between Start- and EndSize.
     endSize: int
     /// If set, the seed to use to start testing. Allows reproduction of previous runs.
-    replay: (int * int) option
+    replay: (uint64 * uint64) option
     /// The Arbitrary instances on this class will be merged in back to front order, i.e. instances for the same generated type at the front
     /// of the list will override those at the back. The instances on Arb.Default are always known, and are at the back (so they can always be
     /// overridden)

README.md

@@ -723,7 +723,7 @@ type FsCheckConfig =
     /// The size to use for the last test, when all the tests are passing. The size increases linearly between Start- and EndSize.
     endSize: int
     /// If set, the seed to use to start testing. Allows reproduction of previous runs.
-    replay: (int * int) option
+    replay: (uint64 * uint64) option
     /// The Arbitrary instances on this class will be merged in back to front order, i.e. instances for the same generated type at the front
     /// of the list will override those at the back. The instances on Arb.Default are always known, and are at the back (so they can always be
     /// overridden)
@@ -860,7 +860,7 @@ If a property fails, the output could look like this.
     Result:
       False
     Focus on error:
-      etestProperty (1865288075, 296281834) "addition is not commutative (should fail)"
+      etestProperty (1865288075UL, 296281834UL) "addition is not commutative (should fail)"
 
 The output that Expecto gives you, lets you recreate the exact test (that's from the 18..., 29... seed numbers). It's
 also a good idea to lift inputs and the test-case/parameter combination that failed into its *own* test (which isn't a
@@ -1366,3 +1366,7 @@ This might be due to how terminals/the locking thereof work: try running your te
 
 
 [logary]: https://github.com/logary/logary#using-logary-in-a-library
+
+## Migration notes
+
+- 11.0.0: Any usages of the `replay` (a.k.a `stdGen` with `etestProperty*` functions) config with FsCheck tests will need to be updated to use `uint64` by appending `UL` to the literals, e.g. from `(1865288075, 296281834)` to `(1865288075UL, 296281834UL)`.

RELEASE_NOTES.md

@@ -1,3 +1,9 @@
+### 11.0.0 - 2024-08-12
+* Breaking Change: move `FsCheckConfig.replay` from `int` to `uint64`.
+  * Fixes issue where many FsCheck3 runs could not be replayed since the random seed is too large.
+  * Existing FsCheck 2 users should be able to use the same seeds values, but converted to `uint64`.
+  * `uint64` literals can be defined like `let iAm5 = 5UL`
+
 ### 10.2.1 - 2024-03-15
 * Fix bug where testTask and testCaseTask allow the tasks to start immediately when the test is defined, breaking backward compatibility with testTask.