tasty-groundhog-converters

Tasty Tests for groundhog converters

Latest on Hackage:0.1.0

This package is not currently in any snapshots. If you're interested in using it, we recommend adding it to Stackage Nightly. Doing so will make builds more reliable, and allow stackage.org to host generated Haddocks.

BSD3 licensed and maintained by Scott Murphy

tasty-groundhog-converters

This library provides a tasty, test harness for groundhog and groundhog-converters.

The key functions are:

roundTripConverter :: Arbitrary a => TestName -> (a -> a -> Bool) -> (Converter a b) -> TestTree

and

goldenSqlConverter :: (PersistEntity b) =>  TestName ->  FilePath -> a ->   (b -> b -> Bool) -> Converter a b  ->   TestTree

Which provide tests for serialization (goldenSqlConverter). and isomorphism (roundTripConverter).

These two together allow a user to quickly add simple testing to a database project using groundhog.

Usage

From the example:

data Group = Group {
     _people :: Map Integer Person
         }
 deriving (Eq)


-- | A wrapped representation of a Person
data Person = Person { _unPerson :: String}
  deriving (Eq)


-- | To Build up the converter we have to have an arbitrary instance
instance Arbitrary Person where
  arbitrary = Person <$> arbitrary

-- | An Isomorphism between the representation that is pleasent to use in haskell
-- and the one that makes sense to store i.e. 'PersistEntity' 
personMapConverter :: Converter (Map Integer Person) [(Int64,String)]
personMapConverter = mapConverter `composeConverter` fmapConverter (bicomposeConverter integerConverter personConverter)

-- | This converter is embedded in 'personMapConverter'
personConverter :: Converter Person String
personConverter = (_unPerson,Person)


-- | A declaration for group.
mkPersist defaultCodegenConfig [groundhog|
- entity: Group
  constructors:
  - name: Group
    fields:
      - name: _people
        dbName: people
        exprName: MappedIdToPerson
        converter: personMapConverter
- primitive: Person
  converter: personConverter


|]


-- | build a golden test (a single test designed to make sure a representation stays constant over time).
-- The aGroup provided is only used the first time the test is used.  The converter at the top level here
-- is just (id, id) and (==) is used because there is an Eq instance on Group.
exampleGoldenSqlConverter :: TestTree
exampleGoldenSqlConverter = goldenSqlConverter "Test The test GoldenSqlConverter" "TestGolden" aGroup (==) (id,id) 
  where
    aGroup = Group somePeople
    somePeople = (Map.fromList . zip [1 ..] . fmap Person ) ["Margret"]

-- | There are no database hits on a round trip test
-- Converter makes the claim that a Converter is an Isomorphism between the two DataTypes.
-- Round trip tests should verify this.
exampleRoundTripTest :: TestTree
exampleRoundTripTest = roundTripConverter "roundtrip personMapConverter" (==) personMapConverter 

-- | call the example test
tastyTest :: IO ()
tastyTest = defaultMain allTests
 where
    allTests = testGroup "all example groundhog converter tests" [ exampleGoldenSqlConverter
                                                                 , exampleRoundTripTest]

Changes

Revision history for tasty-groundhog-converters

0.1.0 -- 2016-03-18

  • First version. Released on an unsuspecting world.

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