Reject nil overrides of state_at fields (#38)

Author: jeremykimber

lib/stator/integration.rb

@@ -158,7 +158,7 @@ def _attempt_to_track_change(field_name)
       return unless @record.respond_to?(field_name)
       return unless @record.respond_to?("#{field_name}=")
       return unless @record.send(field_name.to_s).nil? || state_changed?
-      return if @record.will_save_change_to_attribute?(field_name)
+      return if @record.will_save_change_to_attribute?(field_name) && !@record.send(field_name.to_s).nil?
 
       @record.send("#{field_name}=", (Time.zone || Time).now)
     end

lib/stator/version.rb

@@ -3,7 +3,7 @@
 module Stator
 
   MAJOR       = 0
-  MINOR       = 8
+  MINOR       = 9
   PATCH       = 0
   PRERELEASE  = nil
 

spec/model_spec.rb

@@ -396,6 +396,35 @@
       u.semiactivated_state_at.should eql(t)
     end
 
+    it "should not respect an explicitly provided nil value for a timestamp field in create" do
+      u = User.create!(
+        email: "doug@example.com",
+        state: "semiactivated",
+        semiactivated_state_at: nil
+      )
+
+      u.state.should eql("semiactivated")
+      u.semiactivated_state_at.should_not be_nil
+    end
+
+    it "should not allow an explicitly provided nil value for a timestamp field to override a state transition" do
+      u = User.create!(
+        email: "doug@example.com",
+        state: "semiactivated",
+      )
+
+      u.state.should eql("semiactivated")
+
+      u.activated_state_at = Time.now
+      u.save!
+
+      u.assign_attributes(activated_state_at: nil)
+      u.activate!
+
+      u.state.should eql("activated")
+      u.activated_state_at.should_not be_nil
+    end
+
     it "should allow opting into track by namespace" do
       z = ZooKeeper.new(name: "Doug")
       z.employment_state.should eql("hired")