diff --git a/.gitignore b/.gitignore
index ace5640e..17ef9ac2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -20,3 +20,4 @@ vendor/*
 .tags_sorted_by_file
 .ruby-version
 .ruby-gemset
+.rbenv-gemsets
diff --git a/test/unit/model_test.rb b/test/unit/model_test.rb
index f86e79e8..c40e4ff7 100644
--- a/test/unit/model_test.rb
+++ b/test/unit/model_test.rb
@@ -645,17 +645,28 @@ class HasPaperTrailModelTest < ActiveSupport::TestCase
       assert_not_nil @wotsit.versions.last.reify.updated_at
     end
 
+    # Tests that it doesn't try to write created_on as an attribute just because
+    # a created_on method exists.
+    #
+    # - Deprecation warning in Rails 3.2
+    # - ActiveModel::MissingAttributeError in Rails 4
+    #
+    # In rails 5, `capture` is deprecated in favor of `capture_io`.
+    #
     should 'not generate warning' do
-      # Tests that it doesn't try to write created_on as an attribute just because a created_on
-      # method exists.
-      warnings = capture(:stderr) {  # Deprecation warning in Rails 3.2
-        assert_nothing_raised {  # ActiveModel::MissingAttributeError in Rails 4
+      assert_update_raises_nothing = -> {
+        assert_nothing_raised {
           @wotsit.update_attributes! :name => 'changed'
         }
       }
+      warnings =
+        if respond_to?(:capture_io)
+          capture_io { assert_update_raises_nothing.call }.last
+        else
+          capture(:stderr) { assert_update_raises_nothing.call }
+        end
       assert_equal '', warnings
     end
-
   end