refactor tests -- use programmed image paths.

TestCentre/LibraryTests.fs

@@ -36,6 +36,8 @@
 
         let fixedSkiaImagePath =
             (loadLocation + "/RequiredInfo/Skia-599x336.png")
+        let fixedSystemDrawingImagePath = 
+            (loadLocation + "/RequiredInfo/SystemDrawing-338x307.png")
 
         let allColours =
             let properties =
@@ -345,7 +347,7 @@
         [<Fact>]
         let ``Can determine image width using SkiaSharp`` () =
             let dimensions =
-                SkiaSharp (loadLocation + "/RequiredInfo/Skia-599x336.png")
+                SkiaSharp (fixedSkiaImagePath)
                 |> GridPainter.determineImageDimensions
             let result () = (fst dimensions) = 599
             Assert.True (result ())
@@ -353,7 +355,7 @@
         [<Fact>]
         let ``Can determine image height using SkiaSharp`` () =
             let dimensions =
-                SkiaSharp (loadLocation + "/RequiredInfo/Skia-599x336.png")
+                SkiaSharp (fixedSkiaImagePath)
                 |> GridPainter.determineImageDimensions
             let result () = (snd dimensions) = 336
             Assert.True (result ())
@@ -361,7 +363,7 @@
         [<Fact>]
         let ``Can determine image width using SystemDrawing`` () =
             let dimensions =
-                SystemDrawing (loadLocation + "/RequiredInfo/SystemDrawing-338x307.png")
+                SystemDrawing (fixedSystemDrawingImagePath)
                 |> GridPainter.determineImageDimensions
             let result () = (fst dimensions) = 338
             Assert.True (result ())
@@ -369,7 +371,7 @@
         [<Fact>]
         let ``Can determine image height using SystemDrawing`` () =
             let dimensions =
-                SystemDrawing (loadLocation + "/RequiredInfo/SystemDrawing-338x307.png")
+                SystemDrawing (fixedSystemDrawingImagePath)
                 |> GridPainter.determineImageDimensions
             let result () = (snd dimensions) = 307
             Assert.True (result ())