Add tests (#60)

Gitea.Declarative.Test/Logging.fs

@@ -0,0 +1,34 @@
+namespace Gitea.Declarative.Test
+
+open System
+open Microsoft.Extensions.Logging
+
+[<RequireQualifiedAccess>]
+module LoggerFactory =
+
+    /// Creates a test ILoggerFactory, a sink whose provided inputs you can access through the `unit -> string list`.
+    let makeTest () : ILoggerFactory * (unit -> string list) =
+        let outputs = ResizeArray<_> ()
+
+        let lf =
+            { new ILoggerFactory with
+                member _.Dispose () = ()
+
+                member _.CreateLogger (name : string) =
+                    { new ILogger with
+                        member _.IsEnabled _ = true
+
+                        member _.BeginScope _ =
+                            { new IDisposable with
+                                member _.Dispose () = ()
+                            }
+
+                        member _.Log (_, _, state, exc : exn, formatter) =
+                            let toWrite = formatter.Invoke (state, exc)
+                            lock outputs (fun () -> outputs.Add toWrite)
+                    }
+
+                member _.AddProvider provider = failwith "unsupported"
+            }
+
+        lf, (fun () -> lock outputs (fun () -> Seq.toList outputs))