Testing reify with belongs_to: false

Closes #841, hopefully

README.md

@@ -890,9 +890,6 @@ issues, in order of descending importance.
 1. PaperTrail only reifies the first level of associations.
 1. [#542](https://github.com/airblade/paper_trail/issues/542) -
    Not compatible with [transactional tests][34], aka. transactional fixtures.
-1. [#841](https://github.com/airblade/paper_trail/issues/841) -
-   Without a workaround, reified records cannot be persisted if their associated
-   records have been deleted.
 1. Requires database timestamp columns with fractional second precision.
    - Sqlite and postgres timestamps have fractional second precision by default.
    [MySQL timestamps do not][35]. Furthermore, MySQL 5.5 and earlier do not

test/unit/associations_test.rb

@@ -829,7 +829,7 @@ class AssociationsTest < ActiveSupport::TestCase
             @widget.destroy
           end
 
-          context "when reified" do
+          context "when reified with belongs_to: true" do
             setup { @wotsit2 = @wotsit.versions.last.reify(belongs_to: true) }
 
             should "see the associated as it was at the time" do
@@ -839,6 +839,22 @@ class AssociationsTest < ActiveSupport::TestCase
             should "not persist changes to the live association" do
               assert_nil @wotsit.reload.widget
             end
+
+            should "be able to persist the reified record" do
+              assert_nothing_raised { @wotsit2.save! }
+            end
+          end
+
+          context "when reified with belongs_to: false" do
+            setup do
+              @wotsit2 = @wotsit.versions.last.reify(belongs_to: false)
+            end
+
+            should "save should not re-create the widget record" do
+              # Save succeeds because Wotsit does not validate presence of widget
+              @wotsit2.save!
+              assert_nil ::Widget.find_by(id: @widget.id)
+            end
           end
 
           context "and then the model is updated" do