add Code.ensure_loaded to Duration to ensure pre 1.17 compatibility

Author: joshua-bouv

lib/phoenix_html/safe.ex

@@ -44,8 +44,10 @@ defimpl Phoenix.HTML.Safe, for: DateTime do
   end
 end
 
-defimpl Phoenix.HTML.Safe, for: Duration do
-  defdelegate to_iodata(data), to: Duration, as: :to_iso8601
+if Code.ensure_loaded?(Duration) do
+  defimpl Phoenix.HTML.Safe, for: Duration do
+    defdelegate to_iodata(data), to: Duration, as: :to_iso8601
+  end
 end
 
 defimpl Phoenix.HTML.Safe, for: List do

test/phoenix_html/safe_test.exs

@@ -62,9 +62,11 @@ defmodule Phoenix.HTML.SafeTest do
     assert Safe.to_iodata(datetime) == "2000-01-01T12:13:14+00:30"
   end
 
-  test "impl for Duration" do
-    duration = Duration.new!(month: 1)
-    assert Safe.to_iodata(duration) == "P1M"
+  if Code.ensure_loaded?(Duration) do
+    test "impl for Duration" do
+      duration = Duration.new!(month: 1)
+      assert Safe.to_iodata(duration) == "P1M"
+    end
   end
 
   test "impl for URI" do