Pin down RandomRun behaviour for negative numbers

Author: Janiczek

src/RandomRun.elm

@@ -70,7 +70,7 @@ append : Int -> RandomRun -> RandomRun
 append n run =
     { run
         | length = run.length + 1
-        , data = Queue.enqueue n run.data
+        , data = Queue.enqueue (max 0 n) run.data
     }
 
 
@@ -177,11 +177,7 @@ replaceInList values len list =
     , data =
         List.foldl
             (\( index, newValue ) accList ->
-                if newValue < 0 then
-                    accList
-
-                else
-                    List.setAt index newValue len accList
+                List.setAt index (max 0 newValue) len accList
             )
             list
             values
@@ -272,7 +268,7 @@ set index value run =
             | data =
                 run.data
                     |> Queue.toList
-                    |> List.setAt index value run.length
+                    |> List.setAt index (max 0 value) run.length
                     |> Queue.fromList
         }
 

tests/src/RandomRunTests.elm

@@ -10,7 +10,8 @@ import Test exposing (Test)
 all : Test
 all =
     Test.describe "RandomRun"
-        [ Test.describe "Properties"
+        [ negativeValuesTests
+        , Test.describe "Properties"
             [ isEmptyTests
             , lengthTests
             , compareTests
@@ -31,6 +32,39 @@ all =
         ]
 
 
+negativeValuesTests : Test
+negativeValuesTests =
+    Test.describe "behaviour of negative values"
+        [ Test.test "append -1" <|
+            \() ->
+                RandomRun.empty
+                    |> RandomRun.append -1
+                    |> RandomRun.get 0
+                    |> Expect.equal (Just 0)
+        , Test.test "set -1" <|
+            \() ->
+                RandomRun.empty
+                    |> RandomRun.append 0
+                    |> RandomRun.set 0 -1
+                    |> RandomRun.get 0
+                    |> Expect.equal (Just 0)
+        , Test.test "update (\\_ -> -1)" <|
+            \() ->
+                RandomRun.empty
+                    |> RandomRun.append 0
+                    |> RandomRun.update 0 (\_ -> -1)
+                    |> RandomRun.get 0
+                    |> Expect.equal (Just 0)
+        , Test.test "replace [(0,-1)]" <|
+            \() ->
+                RandomRun.empty
+                    |> RandomRun.append 0
+                    |> RandomRun.replace [ ( 0, -1 ) ]
+                    |> RandomRun.get 0
+                    |> Expect.equal (Just 0)
+        ]
+
+
 isEmptyTests : Test
 isEmptyTests =
     Test.describe "isEmpty"