Implement injection for events (fixes #56)

Examples/ByFeature/FunctionalInjection/FunctionalInjection.fsproj

@@ -5,6 +5,7 @@
     <TargetFrameworks>net6.0;net452</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup>
+    <Compile Include="Logger.fs" />
     <Compile Include="NunitWiring.fs" />
     <Compile Include="StockItem.fs" />
     <EmbeddedResource Include="Stock.feature" />

Examples/ByFeature/FunctionalInjection/Logger.fs

@@ -0,0 +1,22 @@
+module Logger
+
+open TickSpec
+open System
+
+type LogMessages = string list
+
+type LoggerContext = { Messages: LogMessages }
+
+let [<BeforeScenario>] setup () = 
+    { Messages = "Before scenario" |> List.singleton }
+
+let [<BeforeStep>] beforeStep (previousMessages: LoggerContext) =
+    { Messages = "Before step" :: previousMessages.Messages  }
+
+let [<AfterStep>] afterStep (previousMessages: LoggerContext) =
+    { Messages = "After step" :: previousMessages.Messages  }
+
+let [<AfterScenario>] afterScenario (previousMessages: LoggerContext) =
+    "After scenario" :: previousMessages.Messages
+    |> Seq.rev
+    |> Seq.iter Console.WriteLine

RELEASE_NOTES.md

@@ -1,6 +1,7 @@
 #### 2.0.3 (To be released)
 * [Feature] Makes `ScenarioInformation` available to step implementations through arguments resolution (issue #49)
 * [Fix] Performance improvements when the used assembly contains many methods (issue #45)
+* [Feature] Add support for functional injection in events (issue #56)
 * [Fix] Keep empty lines in doc strings (issue #60)
 * [Fix] Allow multiple step types on a single method (issue #55)
 * [Fix] Unit test serialization to allow running from IDE easily

TickSpec/ScenarioGen.fs

@@ -334,6 +334,38 @@ let emitArgument
     else
         emitValue gen providerField parsers paramType arg
 
+/// Emit arguments through injection
+let emitInjectionArguments
+        (gen:ILGenerator)
+        (providerField:FieldBuilder)
+        (parameters: ParameterInfo array) =
+    parameters
+    |> Array.iter (fun p -> emitInstance gen providerField p.ParameterType)
+
+let storeMethodResultInProvider
+        (gen:ILGenerator)
+        (providerField:FieldBuilder)
+        (mi:MethodInfo) =
+    if mi.ReturnType <> typeof<System.Void> then
+        gen.Emit(OpCodes.Box,mi.ReturnType)
+        let local0 = gen.DeclareLocal(typeof<Object>).LocalIndex
+        gen.Emit(OpCodes.Stloc, local0)
+
+        if FSharpType.IsTuple mi.ReturnType then
+            let types = FSharpType.GetTupleElements mi.ReturnType
+            for i = 0 to (types.Length - 1) do
+                let t = types.[i]
+                let local1 = gen.DeclareLocal(typeof<Object>).LocalIndex
+
+                gen.Emit(OpCodes.Ldloc, local0)
+                gen.Emit(OpCodes.Ldc_I4, i)
+                gen.EmitCall(OpCodes.Call, typeof<Microsoft.FSharp.Reflection.FSharpValue>.GetMethod("GetTupleField"), null)
+                gen.Emit(OpCodes.Stloc, local1)
+
+                emitRegisterInstanceCall gen t local1 providerField
+        else
+            emitRegisterInstanceCall gen (mi.ReturnType) local0 providerField
+
 /// Defines step method
 let defineStepMethod
         doc
@@ -442,35 +474,18 @@ let defineStepMethod
         let bulletsCount = line.Bullets |> Option.count
         let docCount = line.Doc |> Option.count
         args.Length + tableCount + bulletsCount + docCount
-    Array.sub ps a (ps.Length - a)
-    |> Array.iter (fun (p:ParameterInfo) ->
-        emitInstance gen providerField p.ParameterType)
+
+    ps
+    |> Array.skip a
+    |> emitInjectionArguments gen providerField
 
     // Emit method invoke
     if mi.IsStatic then
         gen.EmitCall(OpCodes.Call, mi, null)
     else
         gen.Emit(OpCodes.Callvirt, mi)
 
-    if mi.ReturnType <> typeof<System.Void> then
-        gen.Emit(OpCodes.Box,mi.ReturnType)
-        let local0 = gen.DeclareLocal(typeof<Object>).LocalIndex
-        gen.Emit(OpCodes.Stloc, local0)
-
-        if FSharpType.IsTuple mi.ReturnType then
-            let types = FSharpType.GetTupleElements mi.ReturnType
-            for i = 0 to (types.Length - 1) do
-                let t = types.[i]
-                let local1 = gen.DeclareLocal(typeof<Object>).LocalIndex
-
-                gen.Emit(OpCodes.Ldloc, local0)
-                gen.Emit(OpCodes.Ldc_I4, i)
-                gen.EmitCall(OpCodes.Call, typeof<Microsoft.FSharp.Reflection.FSharpValue>.GetMethod("GetTupleField"), null)
-                gen.Emit(OpCodes.Stloc, local1)
-
-                emitRegisterInstanceCall gen t local1 providerField
-        else
-            emitRegisterInstanceCall gen (mi.ReturnType) local0 providerField
+    storeMethodResultInProvider gen providerField mi
 
     // Emit return
     gen.Emit(OpCodes.Ret)
@@ -495,11 +510,16 @@ let defineRunMethod
     // Emit event methods
     let emitEvents =
         Seq.iter (fun (mi:MethodInfo) ->
+            mi.GetParameters()
+            |> emitInjectionArguments gen providerField
+
             if mi.IsStatic then
                 gen.EmitCall(OpCodes.Call, mi, null)
             else
                 emitInstance gen providerField mi.DeclaringType
                 gen.EmitCall(OpCodes.Callvirt, mi, null)
+
+            storeMethodResultInProvider gen providerField mi
         )
 
     beforeScenarioEvents |> emitEvents

TickSpec/ScenarioRun.fs

@@ -17,9 +17,16 @@ let getInstance (provider:IInstanceProvider) (m:MethodInfo) =
     else provider.GetService m.DeclaringType
 
 /// Invokes specified method with specified parameters
-let invoke (provider:IInstanceProvider) (m:MethodInfo) ps =
+let invoke (provider:IInstanceProvider) (m: MethodInfo) (ps: obj array) =
+    let args = [|
+        yield! ps
+
+        for p in m.GetParameters() |> Seq.skip ps.Length do
+            yield provider.GetService p.ParameterType
+    |]
+
     let instance = getInstance provider m
-    let ret = m.Invoke(instance,ps)
+    let ret = m.Invoke(instance, args)
     if m.ReturnType <> typeof<System.Void> then
         if FSharpType.IsTuple m.ReturnType then
             let types = FSharpType.GetTupleElements m.ReturnType
@@ -148,15 +155,9 @@ let invokeStep
             else failwithf "Expected a Table or array argument at position %d" args.Length
         | None,None,Some doc -> [|box doc|]
         | _,_,_ -> [||]
-    let args =
-        let stArgs = Array.append args tail
-        let injectionArgs = 
-            let pars = meth.GetParameters()
-            let a = stArgs.Length
-            Array.sub pars a (pars.Length - a)
-            |> Array.map (fun (p:ParameterInfo) -> provider.GetService(p.ParameterType))
-        Array.append stArgs injectionArgs
-    invoke provider meth args
+
+    Array.append args tail
+    |> invoke provider meth
 
 /// Generate scenario execution function
 let generate events parsers (scenario: ScenarioMetadata, lines) (serviceProviderFactory: Ref<unit -> IInstanceProvider>) =