Test that descriptor key can not be empty

[neongreen]

https://github.com/lyft/ratelimit/blob/master/test/config/config_test.go#L185-L194

[mdimjasevic]

While it would be possible to test this, I'd argue there is not much point in this because the test would hold vacuously. We have this guarantee from Haskell's type checker. This is the definition of the descriptor:

fencer/lib/Fencer/Types.hs

Lines 154 to 161 in 8d627af

	-- | Config for a single rule tree.
	data DescriptorDefinition = DescriptorDefinition
	{ descriptorDefinitionKey :: !RuleKey
	, descriptorDefinitionValue :: !(Maybe RuleValue)
	, descriptorDefinitionRateLimit :: !(Maybe RateLimit)
	, descriptorDefinitionDescriptors :: !(Maybe [DescriptorDefinition])
	}
	deriving stock (Eq, Show)

and this is its FromJSON instance:

fencer/lib/Fencer/Types.hs

Lines 177 to 183 in 8d627af

	instance FromJSON DescriptorDefinition where
	parseJSON = withObject "DescriptorDefinition" $ \o -> do
	descriptorDefinitionKey <- o .: "key"
	descriptorDefinitionValue <- o .:? "value"
	descriptorDefinitionRateLimit <- o .:? "rate_limit"
	descriptorDefinitionDescriptors <- o .:? "descriptors"
	pure DescriptorDefinition{..}

In other words, key has to be there, otherwise we get an exception like this:

2019-11-27T16:39:31Z, E, error loading new configuration from runtime: "nix/ratelimit/ratelimit/config/another.yaml", Aeson exception:
Error in $.descriptors[0].key: parsing Text failed, expected String, but encountered Null

[mdimjasevic]

@neongreen: Can I close this issue?