Support schema's having nil values

Author: keathley

lib/norm/schema.ex

@@ -90,12 +90,13 @@ defmodule Norm.Schema do
     end
 
     defp check_spec({key, spec}, input, path) do
-      val = Map.get(input, key)
+      case Map.has_key?(input, key) do
+        false ->
+          {key, {:error, [error(path ++ [key], input, ":required")]}}
 
-      if val == nil do
-        {key, {:error, [error(path ++ [key], input, ":required")]}}
-      else
-        {key, Conformable.conform(spec, val, path ++ [key])}
+        true ->
+          val = Map.get(input, key)
+          {key, Conformable.conform(spec, val, path ++ [key])}
       end
     end
 

test/norm/schema_test.exs

@@ -58,6 +58,14 @@ defmodule Norm.SchemaTest do
     assert %{bool: false} == conform!(%{bool: false}, s)
   end
 
+  test "allows keys to have nil values" do
+    s = schema(%{foo: spec(is_nil())})
+
+    assert %{foo: nil} == conform!(%{foo: nil}, s)
+    assert {:error, errors} = conform(%{foo: 123}, s)
+    assert errors == ["val: 123 in: :foo fails: is_nil()"]
+  end
+
   describe "generation" do
     test "works with maps" do
       s =