Fix F# option JSON serialization in confirmation/positions API responses

Giraffe 6's default Newtonsoft serializer wrapped F# Some values as
Value/IsSome/IsNone objects, breaking the confirmation and positions
response contract (amounts must be exact decimal strings, absent
fields null, quote object-or-null). Add OptionJsonConverter plus a
shared serializer registration applied to both the Kestrel host and
the in-process test fixture, and cover confirmation/positions over
real HTTP including pending, conflict, cross-fund and Kestrel
restart-replay regressions.

1 files changed, 4 insertions, 1 deletions

diff --git a/tests/FundLab.Api.Tests/PersistenceTests.fs b/tests/FundLab.Api.Tests/PersistenceTests.fs
index 64e857c..5a049af 100644
--- a/tests/FundLab.Api.Tests/PersistenceTests.fs
+++ b/tests/FundLab.Api.Tests/PersistenceTests.fs
@@ -200,7 +200,10 @@ type ApiProcess(connectionString: string) =
 module PersistenceTestHelpers =
     let invoke (handler: HttpHandler) (method: string) (path: string) (headers: (string * string) list) (body: string) =
         let context = DefaultHttpContext()
-        use services = ServiceCollection().AddGiraffe().BuildServiceProvider()
+        use services =
+            (ServiceCollection() |> App.addOptionFriendlyJson)
+                .AddGiraffe()
+                .BuildServiceProvider()
         context.RequestServices <- services
         context.Request.Method <- method