> module TestAppB where
>
> ------------------------------------------------------------------------------
> import           Test.HUnit
> import qualified Data.Map        as M
> ------------------------------------------------------------------------------
> import           Armor
> import           AppB
> ------------------------------------------------------------------------------

Since the new field is a Maybe, we update the old test with a Nothing value
because that's what we expect the serialization to do.  We also add a new test
exercising the new field.  This test should have a new value ID so it gets a
different `.test` file.

> bTests :: ArmorConfig -> Test
> bTests ac = TestList
>     [ testArmor ac "e1" (Employee "Bob" "Smith" 5 Nothing)
>     , testArmor ac "e2" (Employee "Jane" "Doe" 8 (Just 33))
>     , testArmorMany ac $ M.fromList
>         [("e", Executive) , ("m", Manager) , ("w", Worker)]
>     ]

These new tests will pass for the aeson serialization because the generic aeson
deserialization functions will interpret the absence of the age field as a
Nothing. The show serialization will fail because Read for the new data type
requires the age field to be present.