FakeVar enhancements

src/app/Fake.Core.Context/Context.fs

@@ -112,10 +112,20 @@ let forceFakeContext () =
     invalidOp "no Fake Execution context was found. You can initialize one via Fake.Core.Context.setExecutionContext"
   | RuntimeContext.Fake e -> e
 
-let getFakeVar name =
+let getFakeVar<'a> name =
   forceFakeContext()
   |> getFakeContext name
   |> Option.map (fun o -> o :?> 'a)
+
+let getFakeVarOrFail<'a> name =
+  match getFakeVar<'a> name with
+  | Some v -> v
+  | _ -> failwithf "Unable to find FakeVar '%s'" name
+
+let getFakeVarOrDefault<'a> name defaultValue =
+  match getFakeVar<'a> name with
+  | Some v -> v
+  | _ -> defaultValue
 
 let removeFakeVar name =
   forceFakeContext()
@@ -145,4 +155,4 @@ let fakeVarAllowNoContext name =
   (fun (v : 'a) -> 
     if isFakeContext() then
       setFakeVar name v |> ignore
-    else varWithoutContext <- Some v)
+    else varWithoutContext <- Some v)

src/app/Fake.Core.Process/Process.fs

@@ -263,12 +263,12 @@ module Process =
     //let startedProcesses = HashSet()
     let private startedProcessesVar = "Fake.Core.Process.startedProcesses"
     let private getStartedProcesses, _, private setStartedProcesses = 
-        Fake.Core.Context.fakeVar startedProcessesVar
+        Fake.Core.Context.fakeVar<ProcessList> startedProcessesVar
 
     let private doWithProcessList f =
         if Fake.Core.Context.isFakeContext () then
             match getStartedProcesses () with
-            | Some (h:ProcessList) -> Some(f h)
+            | Some h -> Some(f h)
             | None -> 
                 let h = new ProcessList()
                 setStartedProcesses (h)

src/test/Fake.Core.UnitTests/Fake.Core.Context.fs

@@ -4,6 +4,7 @@ open System
 open Fake.Core
 open Expecto
 open Expecto.Flip
+open FParsec.ErrorMessage
 
 [<Tests>]
 let tests = 
@@ -19,5 +20,31 @@ let tests =
            Fake.Core.Context.forceFakeContext() |> ignore
            Tests.failtest "Expected exception"
         with :? System.InvalidOperationException as e -> ()
+
+    testCase "Ability to set and get fake variables" <| fun _ ->
+        Fake.Core.Context.setFakeVar "Test" "TestValue" |> ignore
+        let value = Fake.Core.Context.getFakeVar<string> "Test"
+        Expect.isSome "FakeVar 'Test' is none" value
+        Expect.equal "TestValue" value.Value "FakeVar 'Test' is incorrect"
 
+    testCase "Ability to set and get fake variables with default - when found" <| fun _ ->
+        Fake.Core.Context.setFakeVar "Test" "TestValue" |> ignore
+        let value = Fake.Core.Context.getFakeVarOrDefault<string> "Test" "DefaultValue"
+        Expect.equal "TestValue" value "FakeVar 'Test' is incorrect"
+
+    testCase "Ability to set and get fake variables with default - when not found" <| fun _ ->
+        let value = Fake.Core.Context.getFakeVarOrDefault<string> "Test" "DefaultValue"
+        Expect.equal "DefaultValue" value "FakeVar 'Test' is not the default"
+
+    testCase "Ability to set and get fake variables with failure - when found" <| fun _ ->
+        Fake.Core.Context.setFakeVar "Test" "TestValue" |> ignore
+        let value = Fake.Core.Context.getFakeVarOrFail<string> "Test"
+        Expect.equal "TestValue" value "FakeVar 'Test' is incorrect"
+
+    testCase "Ability to set and get fake variables with default - when not found" <| fun _ ->
+        try
+            Fake.Core.Context.getFakeVarOrFail<string> "Test" |> ignore
+            Tests.failtest "Expected exception"
+        with e ->
+            Expect.equal "Unable to find FakeVar 'Test'" e.Message "Incorrect failure message for FakeVar failure case"
   ]