[tests] fix WithQuery frontend serialization test

Also, add WithQuery pubmed test (with api_key)

test/Test/Offline/JSON.hs

@@ -61,6 +61,7 @@ tests = testGroup "JSON" [
   , testProperty "NodeType roundtrips"      (jsonEnumRoundtrip (Dict @_ @NodeType))
   , testProperty "NodePublishPolicy roundtrips" (jsonEnumRoundtrip (Dict @_ @NodePublishPolicy))
   , testCase "WithQuery frontend compliance" testWithQueryFrontend
+  , testCase "WithQuery frontend compliance (PubMed)" testWithQueryFrontendPubMed
   , testGroup "Phylo" [
     testProperty "PeriodToNode"  (jsonRoundtrip @PeriodToNodeData)
   , testProperty "GraphData"     (jsonRoundtrip @GraphData)
@@ -81,11 +82,23 @@ testWithQueryFrontend = do
    Left err -> fail $ "JSON instance will break frontend!: JSON decoding returned: " <> err
    Right _ -> pure ()
 
+testWithQueryFrontendPubMed :: Assertion
+testWithQueryFrontendPubMed = do
+  case  eitherDecode @WithQuery (C8.pack cannedWithQueryPayloadPubMed) of
+   Left err -> fail $ "JSON instance will break frontend (PubMed)!: JSON decoding returned: " <> err
+   Right _ -> pure ()
+
 -- The aim of this type is to catch regressions in the frontend serialisation; this
 -- is what the frontend currently expects, and therefore if we were to change the JSON
 -- instances, this test would fail, and we will be notified.
 cannedWithQueryPayload :: String
-cannedWithQueryPayload = [r| {"query":"Haskell","node_id":138,"lang":"EN","flowListWith":{"type":"MyListsFirst"},"datafield": { "External": "Arxiv"},"databases":"Arxiv"} |]
+cannedWithQueryPayload = [r| {"query":"Haskell","node_id":138,"lang":"EN","flowListWith":{"type":"MyListsFirst"},"datafield": { "External": {"db": "Arxiv"}}} |]
+
+  -- The aim of this type is to catch regressions in the frontend serialisation; this
+-- is what the frontend currently expects, and therefore if we were to change the JSON
+-- instances, this test would fail, and we will be notified.
+cannedWithQueryPayloadPubMed :: String
+cannedWithQueryPayloadPubMed = [r| {"query":"Haskell","node_id":138,"lang":"EN","flowListWith":{"type":"MyListsFirst"},"datafield": { "External": {"db": "PubMed", "api_key": "x"}}} |]
 
 testParseBpaPhylo :: Assertion
 testParseBpaPhylo = do