Added exception tests for RequestTextFromFile -- invalid gibberishLevel.

Added functions for file input generation in Test Centre.

TestCentre/InputGeneration.fs

@@ -1,6 +1,7 @@
 module InputGeneration
 
     open System
+    open TestingConstants
 
     let ValidGibberishLevelInput () =
             let testInputs = [|2 .. 20|]
@@ -15,3 +16,8 @@
         testInputs.[index]
 
     let InvalidSentencesInput () = System.Random().Next(-5, 1)
+
+    let ValidFileInput () =
+        let testInputs = [|ConsoleWaterworks; DesktopClock; TestPost; WordGenerator|]
+        let index = Random().Next(0, testInputs.Length)
+        testInputs.[index]

TestCentre/PropertyTests.fs

@@ -218,6 +218,15 @@
             let results =
                 lazy Assert.Throws<ArgumentException>(fun () -> test |> ignore)
             Check.Quick results
+
+        [<Property>]
+        let ``RequestTextFromFile throws an ArgumentException when the gibberishLeel in invalid`` () =
+            let test =
+                Pancake.RequestTextFromFileAsync (InvalidGibberishInput()) (ValidSentencesInput()) (ValidFileInput())
+                |> Async.RunSynchronously
+            let results =
+                lazy Assert.Throws<ArgumentException>(fun () -> test |> ignore)
+            Check.Quick results
 (*
 let SentencesIsValid sentences =
 let FilePathIsValid filePath 

TestCentre/TestingConstants.fs

@@ -13,3 +13,9 @@ let WordGenerator = __SOURCE_DIRECTORY__ +  @"\TextFiles\word-generator.txt"
 
 [<Literal>]
 let TestPost = __SOURCE_DIRECTORY__ + @"\TextFiles\test-post.txt"
+
+[<Literal>]
+let InvalidFilePathInput = __SOURCE_DIRECTORY__ + @"Invalid/file.txt"
+
+[<Literal>]
+let InvalidFileTypeInput = __SOURCE_DIRECTORY__ + @"\TextFiles\desktop-clock-info.doc"

TestCentre/UnitTests.fs

@@ -182,3 +182,10 @@ let FilePathIsValid filePath
                 Pancake.RequestTextAsync (ValidGibberishLevelInput()) (InvalidSentencesInput())
                 |> Async.RunSynchronously
             lazy Assert.Throws<ArgumentException>(fun () -> test |> ignore)
+
+        [<Fact>]
+        let ``RequestTextFromFile throws an ArgumentException when the gibberishLevel is invalid`` () =
+            let test () =
+                Pancake.RequestTextFromFileAsync (InvalidGibberishInput())  (ValidSentencesInput()) (ValidFileInput())
+                |> Async.RunSynchronously
+            lazy Assert.Throws<ArgumentException>(fun () -> test |> ignore)