add unit tests for invalid input (createSkiaDataAsync)

DeathSocket/ColourServices.fs

@@ -2,8 +2,6 @@
 
     open System.Drawing
     open DeathSocket.Domain
-    open System
-    open SkiaSharp
 
     let makeBrushFromRGBASpec (spec: RGBASpec) =
         let a = int spec.alpha

DeathSocket/GridPainter.fs

@@ -107,8 +107,8 @@ namespace DeathSocket
                 printfn "%s" ex.Message
                 reraise ()
 
-        // System.Drawing Functions
-        // ====================================================================
+        (* System.Drawing Functions
+        ==================================================================== *)
 
         /// <summary>
         /// Determines the (Pen) points needed to draw the appropriate number
@@ -171,8 +171,8 @@ namespace DeathSocket
         let makeSolidBrushFromRGBASpec (spec: RGBASpec) =
             makeBrushFromRGBASpec spec
 
-        // SkiaSharp Functions
-        // ====================================================================
+        (* SkiaSharp Functions
+        ==================================================================== *)
 
         // NOT TESTED
         

DeathSocket/ImageServices.fs

@@ -8,7 +8,7 @@
     open SkiaSharp
     open System
 
-    (* Why the Use of Repeated Code
+    (* Note on the Use of Repeated Code
     ===========================================================================
     In this file, you will find code which seems duplicated. The areas in
     question are mostly the graphics/drawing parts of the file. Before you
@@ -17,7 +17,7 @@
     also, means it is difficult to pass/return them from one function to the
     next. Therefore, the decision made was to accept the duplicated code in
     exchange for a smaller memory footprint. Several (large) undisposed images
-    lurking in an end users RAM can grid their computer to a halt. On top of
+    lurking in an end users RAM can grind their computer to a halt. On top of
     that, they have no means to make alterations to the code. *)
 
     let setLineThickness pDimension aDimension lineWidth =

TestCentre/LibraryTests.fs

@@ -221,11 +221,96 @@
 
     module UnitTests =
 
-        open TestingHelpers
-        open Xunit
-        open DeathSocket
         open System
         open System.IO
+        open System.Drawing
+        open Xunit
+        open DeathSocket
+        open SkiaSharp
+        open TestingHelpers
+
+        [<Fact>]
+        let ``An empty SKData object is returned when createSKDataAsync cannot find file when using SkiaBuffer`` () =
+            let result =
+                SkiaBuffer ({ filePath = "invalid-file-path"
+                              penWidth = float32 1
+                              skColour = SKColors.Empty
+                              rows = 1
+                              columns = 1 })
+                |> GridPainter.createSKDataAsync
+                |> Async.RunSynchronously
+            Assert.Equal(SKData.Empty, result)
+
+        [<Fact>]
+        let ``An empty SKData object is returned when createSKDataAsync cannot find file when using SkiaRGBBuffer`` () =
+            let result =
+                SkiaRGBBuffer ({ filePath = "invalid-file-path"
+                                 penWidth = float32 1
+                                 red = float32 1
+                                 green = float32 1
+                                 blue = float32 1
+                                 rows = 1
+                                 columns = 1 })
+                |> GridPainter.createSKDataAsync
+                |> Async.RunSynchronously
+            Assert.Equal(SKData.Empty, result)
+
+        [<Fact>]
+        let ``An empty SKData object is returned when calling createSKDataAsync with SkiaRGB`` () =
+            let result =
+                SkiaRGB ({ originalPath = "not needed"
+                           savePath= "not needed"
+                           red = float32 1
+                           green = float32 1
+                           blue = float32 1
+                           penWidth = float32 1
+                           rows = 1
+                           columns = 1})
+                |> GridPainter.createSKDataAsync
+                |> Async.RunSynchronously
+            Assert.Equal(SKData.Empty, result)
+
+        [<Fact>]
+        let ``An empty SKData object is returned when calling createSKDataAsync with Skia`` () =
+            let result =
+                Skia ({ originalPath = "not needed"
+                        savePath= "not needed"
+                        skColour = SKColors.Empty
+                        penWidth = float32 1
+                        rows = 1
+                        columns = 1 })
+                |> GridPainter.createSKDataAsync
+                |> Async.RunSynchronously
+            Assert.Equal(SKData.Empty, result)
+
+        [<Fact>]
+        let ``An empty SKData object is returned when calling createSKDataAsync with Brush`` () =
+            let result =
+                Brush ({ originalPath = "not needed"
+                         savePath= "not needed"
+                         colour = Brushes.AliceBlue
+                         penWidth = float32 1
+                         rows = 1
+                         columns = 1 })
+                |> GridPainter.createSKDataAsync
+                |> Async.RunSynchronously
+            Assert.Equal(SKData.Empty, result)
+
+        [<Fact>]
+        let ``An empty SKData object is returned when calling createSKDataAsync with RGBA`` () =
+            let result =
+                RGBA ({ originalPath = "not needed"
+                        savePath= "not needed"
+                        red = float 1
+                        green = float 1
+                        blue = float 1
+                        alpha = float 1
+                        penWidth = float32 1
+                        rows = 1
+                        columns = 1 })
+                |> GridPainter.createSKDataAsync
+                |> Async.RunSynchronously
+            Assert.Equal(SKData.Empty, result)
 
         [<Fact>]
         let ``Can determine image width using SkiaSharp`` () =