Adds initial keyboard test for right arrow without shift

tests/Spec/KeyboardHelpers.elm

@@ -47,3 +47,12 @@ pressEscKey :
     -> ProgramTest model msg effect
 pressEscKey { targetDetails } =
     pressKey { targetDetails = targetDetails, keyCode = 27, shiftKey = False }
+
+
+pressRightArrow :
+    { targetDetails : List ( String, Encode.Value ) }
+    -> List Selector
+    -> ProgramTest model msg effect
+    -> ProgramTest model msg effect
+pressRightArrow { targetDetails } =
+    pressKey { targetDetails = targetDetails, keyCode = 39, shiftKey = False }

tests/Spec/Nri/Ui/Highlighter.elm

@@ -8,6 +8,7 @@ import Nri.Ui.Highlightable.V1 as Highlightable exposing (Highlightable)
 import Nri.Ui.Highlighter.V1 as Highlighter
 import Nri.Ui.HighlighterTool.V1 as Tool exposing (Tool)
 import ProgramTest exposing (..)
+import Spec.KeyboardHelpers as KeyboardHelpers
 import Test exposing (..)
 import Test.Html.Query exposing (..)
 import Test.Html.Selector exposing (..)
@@ -24,10 +25,24 @@ keyboardTests : List Test
 keyboardTests =
     [ test "has a focusable element when there is one" <|
         \() ->
-            Highlightable.initFragments Nothing "Pothos thrive in indirect light."
+            Highlightable.initFragments Nothing "Pothos indirect light"
                 |> program marker
                 |> ensureFocusOn "Pothos"
                 |> done
+    , test "moves focus right on right arrow key" <|
+        \() ->
+            Highlightable.initFragments Nothing "Pothos indirect light"
+                |> program marker
+                |> ensureFocusOn "Pothos"
+                |> rightArrow
+                |> ensureFocusOn "indirect"
+                |> rightArrow
+                |> ensureFocusOn "light"
+                -- once we're on the final element, pressing right arrow again should
+                -- _not_ wrap the focus. We should stay right where we are!
+                |> rightArrow
+                |> ensureFocusOn "light"
+                |> done
     ]
 
 
@@ -41,6 +56,12 @@ ensureFocusOn word textContext =
             )
 
 
+rightArrow : TestContext marker -> TestContext marker
+rightArrow =
+    KeyboardHelpers.pressRightArrow { targetDetails = [] }
+        [ attribute (Key.tabbable True) ]
+
+
 marker : Tool ()
 marker =
     Tool.Marker