findBack and find work in reverse

src/fsharp/FSharp.Core.PropertyTests/CollectionModulesConsistency.fs

@@ -7,22 +7,7 @@ open System.Collections.Generic
 
 open NUnit.Framework
 open FsCheck
-
-type Result<'a> = 
-| Success of 'a
-| Error of string
-
-let run f = 
-    try
-        Success(f())
-    with
-    | exn -> Error(exn.Message)
-
-let runAndCheckErrorType f = 
-    try
-        Success(f())
-    with
-    | exn -> Error(exn.GetType().ToString())
+open Utils
 
 let append<'a when 'a : equality> (xs : list<'a>) (xs2 : list<'a>) =
     let s = xs |> Seq.append xs2 

src/fsharp/FSharp.Core.PropertyTests/FSharp.Core.PropertyTests.fsproj

@@ -71,6 +71,7 @@
     <Reference Include="System.Observable" Condition="'$(TargetFramework)' == 'sl3-wp' " />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="Utils.fs" />
     <Compile Include="ListProperties.fs" />
     <Compile Include="SeqProperties.fs" />
     <Compile Include="ArrayProperties.fs" />

src/fsharp/FSharp.Core.PropertyTests/ListProperties.fs

@@ -7,6 +7,7 @@ open System.Collections.Generic
 
 open NUnit.Framework
 open FsCheck
+open Utils
 
 let chunkBySize_and_collect<'a when 'a : equality> (xs : 'a list) size =
     size > 0 ==> (lazy
@@ -109,6 +110,32 @@ let ``find and exists work similar`` () =
     Check.QuickThrowOnFailure find_and_exists<string>
     Check.QuickThrowOnFailure find_and_exists<NormalFloat>
 
+let findBack_and_exists<'a when 'a : comparison>  (xs : list<'a>) f =
+    let a = 
+        try
+            List.findBack f xs |> ignore
+            true
+        with
+        | _ -> false
+    let b = List.exists f xs
+    a = b
+
+[<Test>]
+let ``findBack and exists work similar`` () =   
+    Check.QuickThrowOnFailure findBack_and_exists<int>
+    Check.QuickThrowOnFailure findBack_and_exists<string>
+    Check.QuickThrowOnFailure findBack_and_exists<NormalFloat>
+
+let findBack_and_find<'a when 'a : comparison>  (xs : list<'a>) predicate =
+    let a = run (fun () -> xs |> List.findBack predicate)
+    let b = run (fun () -> xs |> List.rev |> List.find predicate)
+    a = b
+
+[<Test>]
+let ``findBack and find work in reverse`` () =   
+    Check.QuickThrowOnFailure findBack_and_find<int>
+    Check.QuickThrowOnFailure findBack_and_find<string>
+    Check.QuickThrowOnFailure findBack_and_find<NormalFloat>
 
 let distinct_works_like_set<'a when 'a : comparison> (xs : 'a list) =
     let a = List.distinct xs

src/fsharp/FSharp.Core.PropertyTests/Utils.fs

@@ -0,0 +1,19 @@
+// Copyright (c) Microsoft Open Technologies, Inc.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+module FSharp.Core.PropertyTests.Utils
+
+type Result<'a> = 
+| Success of 'a
+| Error of string
+
+let run f = 
+    try
+        Success(f())
+    with
+    | exn -> Error(exn.Message)
+
+let runAndCheckErrorType f = 
+    try
+        Success(f())
+    with
+    | exn -> Error(exn.GetType().ToString())