rename cursor functions, add tests

lib/flop.ex

@@ -621,7 +621,7 @@ defmodule Flop do
   defp apply_cursor(q, nil, _), do: q
 
   defp apply_cursor(q, cursor, ordering) do
-    cursor = Cursor.decode_cursor(cursor)
+    cursor = Cursor.decode(cursor)
 
     Enum.reduce(ordering, q, fn {direction, field}, q ->
       case direction do

lib/flop/cursor.ex

@@ -7,17 +7,17 @@ defmodule Flop.Cursor do
   Encodes a cursor value.
   """
   @doc since: "0.8.0"
-  @spec encode_cursor(map()) :: binary()
-  def encode_cursor(key) do
+  @spec encode(map()) :: binary()
+  def encode(key) do
     Base.url_encode64(:erlang.term_to_binary(key))
   end
 
   @doc """
   Decodes a cursor value.
   """
   @doc since: "0.8.0"
-  @spec decode_cursor(binary()) :: map()
-  def decode_cursor(encoded) do
+  @spec decode(binary()) :: map()
+  def decode(encoded) do
     encoded
     |> Base.url_decode64!()
     |> :erlang.binary_to_term([:safe])
@@ -43,6 +43,10 @@ defmodule Flop.Cursor do
     |> Enum.reduce({}, &Tuple.append(&2, &1))
   end
 
+  defp sanitize(_) do
+    raise "invalid cursor value"
+  end
+
   @doc """
   Retrieves the start and end cursors from a query result.
   """
@@ -58,11 +62,11 @@ defmodule Flop.Cursor do
 
       [first | _] ->
         {
-          first |> get_cursor_value_func.(order_by) |> encode_cursor(),
+          first |> get_cursor_value_func.(order_by) |> encode(),
           results
           |> List.last()
           |> get_cursor_value_func.(order_by)
-          |> encode_cursor()
+          |> encode()
         }
     end
   end

lib/flop/relay.ex

@@ -189,6 +189,6 @@ defmodule Flop.Relay do
   end
 
   defp get_cursor(node, order_by, get_cursor_value_func) do
-    node |> get_cursor_value_func.(order_by) |> Cursor.encode_cursor()
+    node |> get_cursor_value_func.(order_by) |> Cursor.encode()
   end
 end

test/flop/cursor_test.exs

@@ -0,0 +1,20 @@
+defmodule Flop.CursorTest do
+  use ExUnit.Case, async: true
+
+  alias Flop.Cursor
+
+  describe "encoding/decoding" do
+    test "encoding and decoding returns original value" do
+      value = %{a: "b", c: [:d], e: {:f, "g", 5}}
+      assert value |> Cursor.encode() |> Cursor.decode() == value
+    end
+
+    test "cursor value containing function results in error" do
+      value = %{a: fn b -> b * 2 end}
+
+      assert_raise RuntimeError, fn ->
+        value |> Cursor.encode() |> Cursor.decode()
+      end
+    end
+  end
+end