Split FsCheck data generators into a helper library (#716)

* Move generators and assertions to helper library.

* Add example usage to bezier curve tests.

* Add FsCheck to OpenTK.Tests.Math via paket.

* Tweak fsharp msbuild settings for OpenTK.Tests.Generators.

OpenTK.sln

@@ -41,6 +41,8 @@ Project("{F2A71F9B-5D33-465A-A702-920D77279786}") = "OpenTK.Tests.Integration",
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "OpenTK.Tests.Math", "tests\OpenTK.Tests.Math\OpenTK.Tests.Math.csproj", "{C2B07CD9-B388-4FC3-AF31-C648F7EA904E}"
 EndProject
+Project("{F2A71F9B-5D33-465A-A702-920D77279786}") = "OpenTK.Tests.Generators", "tests\OpenTK.Tests.Generators\OpenTK.Tests.Generators.fsproj", "{2B11AAEB-D8AC-4356-938F-532D720E0C30}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -91,6 +93,10 @@ Global
 		{C2B07CD9-B388-4FC3-AF31-C648F7EA904E}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{C2B07CD9-B388-4FC3-AF31-C648F7EA904E}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{C2B07CD9-B388-4FC3-AF31-C648F7EA904E}.Release|Any CPU.Build.0 = Release|Any CPU
+		{2B11AAEB-D8AC-4356-938F-532D720E0C30}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{2B11AAEB-D8AC-4356-938F-532D720E0C30}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{2B11AAEB-D8AC-4356-938F-532D720E0C30}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{2B11AAEB-D8AC-4356-938F-532D720E0C30}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -99,5 +105,6 @@ Global
 		{6801C263-ADDA-4A7B-979D-649BCB5A1DF7} = {1857BB8E-1A35-4EBF-9F6D-685F11DC025B}
 		{522D9279-3ED6-475F-867A-6AE69A53C24A} = {1857BB8E-1A35-4EBF-9F6D-685F11DC025B}
 		{C2B07CD9-B388-4FC3-AF31-C648F7EA904E} = {1857BB8E-1A35-4EBF-9F6D-685F11DC025B}
+		{2B11AAEB-D8AC-4356-938F-532D720E0C30} = {1857BB8E-1A35-4EBF-9F6D-685F11DC025B}
 	EndGlobalSection
 EndGlobal

tests/OpenTK.Tests.Generators/Assertions.fs

@@ -1,4 +1,4 @@
-namespace OpenTK.Tests
+namespace OpenTK.Tests.Generators
 
 open Xunit
 open FsCheck
@@ -7,7 +7,7 @@ open System
 open OpenTK
 
 [<AutoOpen>]
-module private AssertHelpers =
+module public AssertHelpers =
     [<Literal>]
     let private BitAccuracy = 16
 
@@ -30,7 +30,7 @@ module private AssertHelpers =
 
 /// We use a full type here instead of a module, as the overloading semantics are more suitable for our desired goal.
 [<Sealed>]
-type internal Assert =
+type public Assert =
 
     static member ApproximatelyEquivalent(a : Vector2,b : Vector2) =
         if not <| approxEq a.X b.X && approxEq a.Y b.Y then raise <| new Xunit.Sdk.EqualException(a,b)

tests/OpenTK.Tests.Generators/Generators.fs

@@ -1,8 +1,6 @@
-namespace OpenTK.Tests
+namespace OpenTK.Tests.Generators
 
-open Xunit
 open FsCheck
-open FsCheck.Xunit
 open System
 open OpenTK
 
@@ -66,7 +64,7 @@ module private Generators =
         |> Gen.map Matrix4
         |> Arb.fromGen
 
-type OpenTKGen =
+type public OpenTKGen =
     static member Single() = single
     static member float32() = single
     static member Double() = double

tests/OpenTK.Tests.Generators/paket.references

@@ -0,0 +1,2 @@
+xunit
+FsCheck.XUnit

tests/OpenTK.Tests.Math/BezierCurveTests.cs

@@ -1,16 +1,38 @@
-using Xunit;
+using FsCheck.Xunit;
+using OpenTK.Tests.Generators;
+using Xunit;
+using Assert = Xunit.Assert;
 
-namespace OpenTK.Tests.Unit
+namespace OpenTK.Tests.Math
 {
     public class BezierCurveTests
     {
-        [Fact]
-        public void StraightLine()
+        [Properties(Arbitrary = new[] { typeof(OpenTKGen) })]
+        public class Constructor
         {
-            var curve = new BezierCurve(Vector2.Zero, Vector2.One);
-            Assert.Equal(Vector2.Zero, curve.CalculatePoint(0.0f));
-            Assert.Equal(Vector2.One, curve.CalculatePoint(1.0f));
-            Assert.Equal(new Vector2(0.5f, 0.5f), curve.CalculatePoint(0.5f));
+            [Property]
+            public void AcceptingVector2EnumerableCreatesCurveContainingThePointsInTheEnumerable
+                (Vector2 a, Vector2 b, Vector2 c, Vector2 d)
+            {
+                var expected = new[] { a, b, c, d };
+
+                var curve = new BezierCurve(expected);
+
+                var actual = curve.Points;
+                Assert.Equal(expected, actual);
+            }
+        }
+
+        public class CalculatePoint
+        {
+            [Fact]
+            public void StraightLine()
+            {
+                var curve = new BezierCurve(Vector2.Zero, Vector2.One);
+                Assert.Equal(Vector2.Zero, curve.CalculatePoint(0.0f));
+                Assert.Equal(Vector2.One, curve.CalculatePoint(1.0f));
+                Assert.Equal(new Vector2(0.5f, 0.5f), curve.CalculatePoint(0.5f));
+            }
         }
     }
 }

tests/OpenTK.Tests.Math/paket.references

@@ -4,3 +4,4 @@ xunit
 xunit.abstractions
 xunit.extensibility.core
 xunit.extensibility.execution
+FsCheck.XUnit

tests/OpenTK.Tests/MathHelperTests.fs

@@ -5,6 +5,7 @@ open FsCheck
 open FsCheck.Xunit
 open System
 open OpenTK
+open OpenTK.Tests.Generators
 
 module MathHelper =
     [<Properties(Arbitrary = [| typeof<OpenTKGen> |])>]

tests/OpenTK.Tests/Matrix4Tests.fs

@@ -5,6 +5,7 @@ open FsCheck
 open FsCheck.Xunit
 open System
 open OpenTK
+open OpenTK.Tests.Generators
 
 module Matrix4 =
     [<Properties(Arbitrary = [| typeof<OpenTKGen> |])>]

tests/OpenTK.Tests/OpenTK.Tests.fsproj

@@ -62,8 +62,6 @@
   -->
   <ItemGroup>
     <Compile Include="AssemblyInfo.fs" />
-    <Compile Include="Assertions.fs" />
-    <Compile Include="Generators.fs" />
     <Compile Include="MathHelperTests.fs" />
     <Compile Include="Matrix4Tests.fs" />
     <Compile Include="Vector2Tests.fs" />
@@ -74,6 +72,10 @@
     <None Include="paket.references" />
   </ItemGroup>
   <ItemGroup>
+    <ProjectReference Include="..\OpenTK.Tests.Generators\OpenTK.Tests.Generators.fsproj">
+      <Project>{2b11aaeb-d8ac-4356-938f-532d720e0c30}</Project>
+      <Name>OpenTK.Tests.Generators</Name>
+    </ProjectReference>
     <Reference Include="mscorlib" />
     <Reference Include="System" />
     <Reference Include="System.Core" />

tests/OpenTK.Tests/Vector2Tests.fs

@@ -6,6 +6,7 @@ open FsCheck.Xunit
 open System
 open System.Runtime.InteropServices
 open OpenTK
+open OpenTK.Tests.Generators
 
 module Vector2 =
     [<Properties(Arbitrary = [| typeof<OpenTKGen> |])>]

tests/OpenTK.Tests/Vector3Tests.fs

@@ -6,6 +6,7 @@ open FsCheck.Xunit
 open System
 open System.Runtime.InteropServices
 open OpenTK
+open OpenTK.Tests.Generators
 
 module Vector3 =
     [<Properties(Arbitrary = [| typeof<OpenTKGen> |])>]

tests/OpenTK.Tests/Vector4Tests.fs

@@ -6,6 +6,7 @@ open FsCheck.Xunit
 open System
 open System.Runtime.InteropServices
 open OpenTK
+open OpenTK.Tests.Generators
 
 module Vector4 =
     [<Properties(Arbitrary = [| typeof<OpenTKGen> |])>]