Merge pull request rails#6715 from arunagw/add_asserts

Need a assert here in tests

Author: rafaelfranca

activerecord/test/cases/mass_assignment_security_test.rb

@@ -95,11 +95,11 @@ def test_mass_assigning_invalid_attribute
   end
 
   def test_mass_assigning_does_not_choke_on_nil
-    Firm.new.assign_attributes(nil)
+    assert_nil Firm.new.assign_attributes(nil)
   end
 
   def test_mass_assigning_does_not_choke_on_empty_hash
-    Firm.new.assign_attributes({})
+    assert_nil Firm.new.assign_attributes({})
   end
 
   def test_assign_attributes_uses_default_role_when_no_role_is_provided