Fix snake_cased_map_keys not ignoring structs

lib/simplificator_3000/map_helpers.ex

@@ -1,5 +1,8 @@
 defmodule Simplificator3000.MapHelpers do
   alias Simplificator3000.StringHelpers
+  # TODO fix inconsistent behavion
+  # camel cased map keys converts almost all struct to map, because its used to convert result to json response
+  # but snake_cased_map_keys is used to convert user input to snake case, so it should not convert structs to maps
 
   def camel_cased_map_keys(%DateTime{} = val), do: val
 
@@ -25,7 +28,9 @@ defmodule Simplificator3000.MapHelpers do
 
   def camel_cased_map_keys(val), do: val
 
-  def snake_cased_map_keys(%{} = map) do
+  def snake_cased_map_keys(struct = %_{}), do: struct
+
+  def snake_cased_map_keys(map) when is_map(map) do
     for {key, val} <- map, into: %{} do
       {StringHelpers.underscore(key), snake_cased_map_keys(val)}
     end

mix.exs

@@ -4,7 +4,7 @@ defmodule Simplificator3000.MixProject do
   def project do
     [
       app: :simplificator_3000,
-      version: "0.5.4",
+      version: "0.5.5",
       elixir: "~> 1.11",
       start_permanent: Mix.env() == :prod,
       name: "Simplificator3000",

test/simplificator_3000/map_helpers_test.exs

@@ -1,4 +1,40 @@
 defmodule Simplificator3000.MapHelpersTest do
   use ExUnit.Case
   doctest Simplificator3000.MapHelpers
+
+  test "snake case map keys" do
+    struct = %{
+      "camelCase" => "camelCase",
+      "Snake_case" => "snake_case",
+      "snake_case" => %{
+        "camelCase" => "camelCase",
+        "snake_case" => "snake_case"
+      }
+    }
+
+    expected = %{
+      "camel_case" => "camelCase",
+      "snake_case" => "snake_case",
+      "snake_case" => %{
+        "camel_case" => "camelCase",
+        "snake_case" => "snake_case"
+      }
+    }
+
+    assert Simplificator3000.MapHelpers.snake_cased_map_keys(struct) == expected
+  end
+
+  test "dont break structs" do
+    input = %File.Stat{
+      access: :read,
+      size: 12345
+    }
+
+    expected = %File.Stat{
+      access: :read,
+      size: 12345
+    }
+
+    assert Simplificator3000.MapHelpers.snake_cased_map_keys(input) == expected
+  end
 end