Added some List tests

Author: ncave

src/fable-library/List.fs

@@ -434,8 +434,8 @@ let slice (lower: int option) (upper: int option) (xs: 'T list) =
     else newList <| xs.Values.GetRange(xs.Count - 1 - upper, upper - lower + 1)
 
 let splitAt i (xs: 'T list) =
-    if i < 0 then invalidArg "i" LanguagePrimitives.ErrorStrings.InputMustBeNonNegativeString
-    if i > xs.Count then invalidArg "i" "The input sequence has an insufficient number of elements."
+    if i < 0 then invalidArg "index" LanguagePrimitives.ErrorStrings.InputMustBeNonNegativeString
+    if i > xs.Count then invalidArg "index" "The input sequence has an insufficient number of elements."
     take i xs, skip i xs
 
 let distinctBy (projection: 'T -> 'Key) (xs: 'T list) ([<Inject>] eq: IEqualityComparer<'Key>) =
@@ -447,8 +447,8 @@ let distinct (xs: 'T list) ([<Inject>] eq: IEqualityComparer<'T>) =
 
 let exactlyOne (xs: 'T list) =
     match xs.Count with
-    | 0 -> invalidArg "list" LanguagePrimitives.ErrorStrings.InputSequenceEmptyString
     | 1 -> head xs
+    | 0 -> invalidArg "list" LanguagePrimitives.ErrorStrings.InputSequenceEmptyString
     | _ -> invalidArg "list" "Input list too long"
 
 let groupBy (projection: 'T -> 'Key) (xs: 'T list)([<Inject>] eq: IEqualityComparer<'Key>): ('Key * 'T list) list =

tests/Main/ListTests.fs

@@ -42,13 +42,26 @@ module List =
 
 let tests =
   testList "Lists" [
-    // TODO: Empty lists may be represented as null, make sure they don't conflict with None
     testCase "Some [] works" <| fun () ->
         let xs: int list option = Some []
         let ys: int list option = None
         Option.isSome xs |> equal true
         Option.isNone ys |> equal true
 
+    testCase "List equality works" <| fun () ->
+        let xs = [1;2;3]
+        let ys = [1;2;3]
+        let zs = [1;4;3]
+        xs = ys |> equal true
+        xs = zs |> equal false
+
+    testCase "List comparison works" <| fun () ->
+        let xs = [1;2;3]
+        let ys = [1;2;3]
+        let zs = [1;4;3]
+        xs < ys |> equal false
+        xs < zs |> equal true
+
     testCase "Pattern matching with lists works" <| fun () ->
         match [] with [] -> true | _ -> false
         |> equal true
@@ -302,9 +315,9 @@ let tests =
             |> List.sum |> equal 9
 
     testCase "List.rev works" <| fun () ->
-            let xs = [1; 2]
+            let xs = [1; 2; 3]
             let ys = xs |> List.rev
-            equal 2 ys.Head
+            equal 3 ys.Head
 
     testCase "List.scan works" <| fun () ->
             let xs = [1; 2; 3; 4]