Implement RestEase variable headers (#76)

WoofWare.Myriad.Plugins.Test/TestHttpClient/TestVariableHeader.fs

@@ -0,0 +1,108 @@
+namespace WoofWare.Myriad.Plugins.Test
+
+open System
+open System.Net
+open System.Net.Http
+open System.Threading
+open NUnit.Framework
+open FsUnitTyped
+open PureGym
+
+[<TestFixture>]
+module TestVariableHeader =
+
+    [<Test>]
+    let ``Headers are set`` () : unit =
+        let proc (message : HttpRequestMessage) : HttpResponseMessage Async =
+            async {
+                message.Method |> shouldEqual HttpMethod.Get
+
+                message.RequestUri.ToString ()
+                |> shouldEqual "https://example.com/endpoint/param"
+
+                let headers =
+                    [
+                        for h in message.Headers do
+                            yield $"%s{h.Key}: %s{Seq.exactlyOne h.Value}"
+                    ]
+                    |> String.concat "\n"
+
+                let content = new StringContent (headers)
+                let resp = new HttpResponseMessage (HttpStatusCode.OK)
+                resp.Content <- content
+                return resp
+            }
+
+        use client = HttpClientMock.make (Uri "https://example.com") proc
+
+        let someHeaderCount = ref 10
+
+        let someHeader () =
+            (Interlocked.Increment someHeaderCount : int).ToString ()
+
+        let someOtherHeaderCount = ref -100
+
+        let someOtherHeader () =
+            Interlocked.Increment someOtherHeaderCount
+
+        let api = ApiWithHeaders.make someHeader someOtherHeader client
+
+        someHeaderCount.Value |> shouldEqual 10
+        someOtherHeaderCount.Value |> shouldEqual -100
+
+        api.GetPathParam("param").Result.Split "\n"
+        |> Array.sort
+        |> shouldEqual [| "Authorization: -99" ; "Header-Name: Header-Value" ; "X-Foo: 11" |]
+
+        someHeaderCount.Value |> shouldEqual 11
+        someOtherHeaderCount.Value |> shouldEqual -99
+
+    [<Test>]
+    let ``Headers get re-evaluated every time`` () : unit =
+        let proc (message : HttpRequestMessage) : HttpResponseMessage Async =
+            async {
+                message.Method |> shouldEqual HttpMethod.Get
+
+                message.RequestUri.ToString ()
+                |> shouldEqual "https://example.com/endpoint/param"
+
+                let headers =
+                    [
+                        for h in message.Headers do
+                            yield $"%s{h.Key}: %s{Seq.exactlyOne h.Value}"
+                    ]
+                    |> String.concat "\n"
+
+                let content = new StringContent (headers)
+                let resp = new HttpResponseMessage (HttpStatusCode.OK)
+                resp.Content <- content
+                return resp
+            }
+
+        use client = HttpClientMock.make (Uri "https://example.com") proc
+
+        let someHeaderCount = ref 10
+
+        let someHeader () =
+            (Interlocked.Increment someHeaderCount : int).ToString ()
+
+        let someOtherHeaderCount = ref -100
+
+        let someOtherHeader () =
+            Interlocked.Increment someOtherHeaderCount
+
+        let api = ApiWithHeaders.make someHeader someOtherHeader client
+
+        someHeaderCount.Value |> shouldEqual 10
+        someOtherHeaderCount.Value |> shouldEqual -100
+
+        api.GetPathParam("param").Result.Split "\n"
+        |> Array.sort
+        |> shouldEqual [| "Authorization: -99" ; "Header-Name: Header-Value" ; "X-Foo: 11" |]
+
+        api.GetPathParam("param").Result.Split "\n"
+        |> Array.sort
+        |> shouldEqual [| "Authorization: -98" ; "Header-Name: Header-Value" ; "X-Foo: 12" |]
+
+        someHeaderCount.Value |> shouldEqual 12
+        someOtherHeaderCount.Value |> shouldEqual -98