[CO-354] Tweak style

- Rename to `canonicalJsonTestWithGen`.
- Use Aeson optional-with-default combinator.

Author: Michael Hueschen

core/src/Pos/Aeson/Core/Configuration.hs

@@ -8,7 +8,7 @@ module Pos.Aeson.Core.Configuration
 
 import           Universum
 
-import           Data.Aeson (FromJSON, parseJSON, withObject, (.:), (.:?))
+import           Data.Aeson (FromJSON, parseJSON, withObject, (.!=), (.:), (.:?))
 import           Data.Aeson.TH (deriveToJSON)
 import           Serokell.Aeson.Options (defaultOptions)
 
@@ -21,11 +21,6 @@ instance FromJSON CoreConfiguration where
     parseJSON = withObject "core" $ \obj -> do
         ccg   <- obj .: "genesis"
         ccdsv <- obj .: "dbSerializeVersion"
-        ccrnm <- determineRNM <$> obj .:? "requiresNetworkMagic"
-        pure $ CoreConfiguration ccg ccdsv ccrnm
-      where
         -- If "requiresNetworkMagic" is not specified, default to NMMustBeJust
-        determineRNM :: Maybe RequiresNetworkMagic -> RequiresNetworkMagic
-        determineRNM mrnm = case mrnm of
-            Nothing -> NMMustBeJust
-            Just x  -> x
+        ccrnm <- obj .:? "requiresNetworkMagic" .!= NMMustBeJust
+        pure $ CoreConfiguration ccg ccdsv ccrnm

lib/src/Test/Pos/Helpers.hs

@@ -7,7 +7,7 @@
 
 module Test.Pos.Helpers
        ( canonicalJsonTest
-       , canonicalJsonTest'
+       , canonicalJsonTestWithGen
        ) where
 
 import           Universum
@@ -41,11 +41,11 @@ canonicalJsonTest =
         canonicalJsonRenderAndDecode x .&&. canonicalJsonPrettyAndDecode x
 
 -- | Basically the same as `canonicalJsonTest` but tests a given `Gen a`.
-canonicalJsonTest'
+canonicalJsonTestWithGen
     :: forall a. (IdTestingRequiredClassesAlmost a, ToAndFromCanonicalJson a)
     => Gen a
     -> Spec
-canonicalJsonTest' genA =
+canonicalJsonTestWithGen genA =
     prop (typeName @a) $ forAll genA $ \x ->
         canonicalJsonRenderAndDecode x .&&. canonicalJsonPrettyAndDecode x
   where

lib/test/Test/Pos/Genesis/CanonicalSpec.hs

@@ -15,7 +15,7 @@ import           Pos.Crypto (RequiresNetworkMagic (..))
 import           Test.Pos.Configuration (withDefConfiguration)
 import           Test.Pos.Core.Arbitrary (genGenesisData, genGenesisProtocolConstants)
 import           Test.Pos.Crypto.Arbitrary (genProtocolMagicUniformWithRNM)
-import           Test.Pos.Helpers (canonicalJsonTest, canonicalJsonTest')
+import           Test.Pos.Helpers (canonicalJsonTest, canonicalJsonTestWithGen)
 
 spec :: Spec
 spec = withDefConfiguration $ \_ -> describe "Genesis" $ modifyMaxSuccess (const 10) $ do
@@ -30,8 +30,8 @@ spec = withDefConfiguration $ \_ -> describe "Genesis" $ modifyMaxSuccess (const
         -- `NMMustBeJust`.
         describe "Generator restricted to only use NMMustBeJust" $ do
             let genPM = genProtocolMagicUniformWithRNM NMMustBeJust
-            canonicalJsonTest' $ genGenesisProtocolConstants genPM
-            canonicalJsonTest' $ genGenesisData (genGenesisProtocolConstants genPM)
+            canonicalJsonTestWithGen $ genGenesisProtocolConstants genPM
+            canonicalJsonTestWithGen $ genGenesisData (genGenesisProtocolConstants genPM)
 
         -- Unrestricted canonical JSON identity tests
         describe "Unrestricted tests" $ do