diff --git a/tests/OpenTK.Tests/OpenTK.Tests.fsproj b/tests/OpenTK.Tests/OpenTK.Tests.fsproj
index 09bd26c0..d269e1c3 100644
--- a/tests/OpenTK.Tests/OpenTK.Tests.fsproj
+++ b/tests/OpenTK.Tests/OpenTK.Tests.fsproj
@@ -64,6 +64,7 @@
     <Compile Include="Matrix4Tests.fs" />
     <Compile Include="Vector2Tests.fs" />
     <Compile Include="Vector3Tests.fs" />
+    <Compile Include="Vector4Tests.fs" />
     <Content Include="App.config" />
     <None Include="paket.references" />
   </ItemGroup>
diff --git a/tests/OpenTK.Tests/Vector3Tests.fs b/tests/OpenTK.Tests/Vector3Tests.fs
index 8ac1b4ae..87b2dc92 100644
--- a/tests/OpenTK.Tests/Vector3Tests.fs
+++ b/tests/OpenTK.Tests/Vector3Tests.fs
@@ -206,6 +206,7 @@ module Vector3 =
             
             Assert.ApproximatelyEqual(a.X + b.X,c.X)
             Assert.ApproximatelyEqual(a.Y + b.Y,c.Y)
+            Assert.ApproximatelyEqual(a.Z + b.Z,c.Z)
         
         [<Property>]
         let ``Vector3 addition is commutative`` (a : Vector3, b : Vector3) = 
diff --git a/tests/OpenTK.Tests/Vector4Tests.fs b/tests/OpenTK.Tests/Vector4Tests.fs
new file mode 100644
index 00000000..b0b9c3a5
--- /dev/null
+++ b/tests/OpenTK.Tests/Vector4Tests.fs
@@ -0,0 +1,789 @@
+namespace OpenTK.Tests
+
+open Xunit
+open FsCheck
+open FsCheck.Xunit
+open System
+open System.Runtime.InteropServices
+open OpenTK
+
+module Vector4 = 
+    [<Properties(Arbitrary = [| typeof<OpenTKGen> |])>]
+    module Constructors = 
+        //
+        [<Property>]
+        let ``Triple value constructor sets all components to the correct values`` (x, y, z, w) = 
+            let v = Vector4(x, y, z, w)
+
+            Assert.Equal(x, v.X)
+            Assert.Equal(y, v.Y)
+            Assert.Equal(z, v.Z)
+            Assert.Equal(w, v.W)
+            
+        [<Property>]
+        let ``Single value constructor sets all components to the correct values`` (a : float32) = 
+            let v = Vector4(a)
+
+            Assert.Equal(a, v.X)
+            Assert.Equal(a, v.Y)
+            Assert.Equal(a, v.Z)
+            Assert.Equal(a, v.W)
+            
+        [<Property>]
+        let ``Vector2 value constructor sets all components to the correct values`` (x, y) = 
+            let v1 = Vector2(x, y)
+            let v2 = Vector4(v1)
+
+            Assert.Equal(v1.X, v2.X)
+            Assert.Equal(v1.Y, v2.Y)
+
+            Assert.Equal(x, v2.X)
+            Assert.Equal(y, v2.Y)
+            Assert.Equal((float32)0, v2.Z)
+            Assert.Equal((float32)0, v2.W)
+            
+        [<Property>]
+        let ``Vector3 value constructor sets all components to the correct values`` (x, y, z) = 
+            let v1 = Vector3(x, y, z)
+            let v2 = Vector4(v1)
+
+            Assert.Equal(v1.X, v2.X)
+            Assert.Equal(v1.Y, v2.Y)
+            Assert.Equal(v1.Z, v2.Z)
+
+            Assert.Equal(x, v2.X)
+            Assert.Equal(y, v2.Y)
+            Assert.Equal(z, v2.Z)
+            Assert.Equal((float32)0, v2.W)
+            
+        [<Property>]
+        let ``Vector4 value constructor sets all components to the correct values`` (x, y, z, w) = 
+            let v1 = Vector4(x, y, z, w)
+            let v2 = Vector4(v1)
+
+            Assert.Equal(v1.X, v2.X)
+            Assert.Equal(v1.Y, v2.Y)
+            Assert.Equal(v1.Z, v2.Z)
+            Assert.Equal(v1.W, v2.W)
+
+            Assert.Equal(x, v2.X)
+            Assert.Equal(y, v2.Y)
+            Assert.Equal(z, v2.Z)
+            Assert.Equal(w, v2.W)
+            
+    [<Properties(Arbitrary = [| typeof<OpenTKGen> |])>]
+    module Indexing = 
+        //
+        [<Property>]
+        let ``Index operator accesses the correct components`` (x, y, z, w) = 
+            let v = Vector4(x, y, z, w)
+            
+            Assert.Equal(x, v.[0])
+            Assert.Equal(y, v.[1])
+            Assert.Equal(z, v.[2])
+            Assert.Equal(w, v.[3])
+            
+        [<Property>]
+        let ``Index operator throws exception for negative indices`` (x, y, z, w) = 
+            let mutable v = Vector4(x, y, z, w)
+            
+            let invalidIndexingAccess = fun() -> v.[-1] |> ignore
+            let invalidIndexingAssignment = fun() -> v.[-1] <- x
+
+            Assert.Throws<IndexOutOfRangeException>(invalidIndexingAccess) |> ignore
+            Assert.Throws<IndexOutOfRangeException>(invalidIndexingAssignment) |> ignore
+            
+        [<Property>]
+        let ``Index operator throws exception for large indices`` (x, y, z, w) = 
+            let mutable v = Vector4(x, y, z, w)
+            
+            let invalidIndexingAccess = fun() -> v.[4] |> ignore
+            let invalidIndexingAssignment = fun() -> v.[4] <- x
+
+            Assert.Throws<IndexOutOfRangeException>(invalidIndexingAccess) |> ignore
+            Assert.Throws<IndexOutOfRangeException>(invalidIndexingAssignment) |> ignore
+            
+    [<Properties(Arbitrary = [| typeof<OpenTKGen> |])>]
+    module Length = 
+        //
+        [<Property>]
+        let ``Length method works`` (x, y, z, w) = 
+            let v = Vector4(x, y, z, w)
+            let l = System.Math.Sqrt((float)(x * x + y * y + z * z + w * w))
+            
+            Assert.Equal((float32)l, v.Length)
+            
+        [<Property>]
+        let ``Fast length method works`` (x, y, z, w) = 
+            let v = Vector4(x, y, z, w)
+            let l = 1.0f / MathHelper.InverseSqrtFast(x * x + y * y + z * z + w * w)
+            
+            Assert.Equal(l, v.LengthFast)
+            
+        [<Property>]
+        let ``Length squared method works`` (x, y, z, w) = 
+            let v = Vector4(x, y, z, w)
+            let lsq = x * x + y * y + z * z + w * w
+            
+            Assert.Equal(lsq, v.LengthSquared)
+            
+    [<Properties(Arbitrary = [| typeof<OpenTKGen> |])>]
+    module Normalization = 
+        //
+        [<Property>]
+        let ``Normalization of instance, creating a new vector, works`` (x, y, z, w) = 
+            let v = Vector4(x, y, z, w)
+            let l = v.Length
+            
+            // Dividing by zero is not supported
+            if not (approxEq l 0.0f) then
+                let norm = v.Normalized()
+    
+                Assert.ApproximatelyEqual(v.X / l, norm.X)
+                Assert.ApproximatelyEqual(v.Y / l, norm.Y)
+                Assert.ApproximatelyEqual(v.Z / l, norm.Z)
+                Assert.ApproximatelyEqual(v.W / l, norm.W)
+
+        [<Property>]
+        let ``Normalization of instance works`` (x, y, z, w) = 
+            let v = Vector4(x, y, z, w)
+            let l = v.Length
+            
+            if not (approxEq l 0.0f) then
+                let norm = Vector4(x, y, z, w)
+                norm.Normalize()
+    
+                Assert.ApproximatelyEqual(v.X / l, norm.X)
+                Assert.ApproximatelyEqual(v.Y / l, norm.Y)
+                Assert.ApproximatelyEqual(v.Z / l, norm.Z)
+                Assert.ApproximatelyEqual(v.W / l, norm.W)
+
+        [<Property>]
+        let ``Fast approximate normalization of instance works`` (x, y, z, w) = 
+            let v = Vector4(x, y, z, w)
+            let norm = Vector4(x, y, z, w)
+            norm.NormalizeFast()
+
+            let scale = MathHelper.InverseSqrtFast(x * x + y * y + z * z + w * w)
+
+            Assert.ApproximatelyEqual(v.X * scale, norm.X)
+            Assert.ApproximatelyEqual(v.Y * scale, norm.Y)
+            Assert.ApproximatelyEqual(v.Z * scale, norm.Z)
+            Assert.ApproximatelyEqual(v.W * scale, norm.W)
+            
+        [<Property>] // TODO: Eliminate coefficient calculation, rounding error
+        let ``Normalization by reference works`` (a : Vector4) =
+            if not (approxEq a.Length 0.0f) then
+                let scale = 1.0f / a.Length
+                let norm = Vector4(a.X * scale, a.Y * scale, a.Z * scale, a.W * scale)
+                let vRes = Vector4.Normalize(ref a)
+                
+                Assert.ApproximatelyEqual(norm, vRes)
+            
+        [<Property>] // TODO: Eliminate coefficient calculation, rounding error
+        let ``Normalization works`` (a : Vector4) =
+            if not (approxEq a.Length 0.0f) then
+                let scale = 1.0f / a.Length
+                let norm = Vector4(a.X * scale, a.Y * scale, a.Z * scale, a.W * scale)
+                
+                Assert.ApproximatelyEqual(norm, Vector4.Normalize(a));
+            
+        [<Property>]
+        let ``Fast approximate normalization by reference works`` (a : Vector4) =
+            let scale = MathHelper.InverseSqrtFast(a.X * a.X + a.Y * a.Y + a.Z * a.Z + a.W * a.W)
+            
+            let norm = Vector4(a.X * scale, a.Y * scale, a.Z * scale, a.W * scale)
+            let vRes = Vector4.NormalizeFast(ref a)
+            
+            Assert.ApproximatelyEqual(norm, vRes)
+            
+        [<Property>]
+        let ``Fast approximate normalization works`` (a : Vector4) =
+            let scale = MathHelper.InverseSqrtFast(a.X * a.X + a.Y * a.Y + a.Z * a.Z + a.W * a.W)
+            
+            let norm = Vector4(a.X * scale, a.Y * scale, a.Z * scale, a.W * scale)
+            
+            Assert.ApproximatelyEqual(norm, Vector4.NormalizeFast(a));
+
+    [<Properties(Arbitrary = [| typeof<OpenTKGen> |])>]
+    module Addition = 
+        //
+        [<Property>]
+        let ``Vector4 addition is the same as component addition`` (a : Vector4, b : Vector4) = 
+            let c = a + b
+            
+            Assert.ApproximatelyEqual(a.X + b.X,c.X)
+            Assert.ApproximatelyEqual(a.Y + b.Y,c.Y)
+            Assert.ApproximatelyEqual(a.Z + b.Z,c.Z)
+            Assert.ApproximatelyEqual(a.W + b.W,c.W)
+        
+        [<Property>]
+        let ``Vector4 addition is commutative`` (a : Vector4, b : Vector4) = 
+            let c = a + b
+            let c2 = b + a
+            
+            Assert.ApproximatelyEqual(c, c2)
+        
+        [<Property>]
+        let ``Vector4 addition is associative`` (a : Vector4, b : Vector4, c : Vector4) = 
+            let r1 = (a + b) + c
+            let r2 = a + (b + c)
+            
+            Assert.ApproximatelyEqual(r1, r2)
+            
+        [<Property>]
+        let ``Static Vector4 addition method is the same as component addition`` (a : Vector4, b : Vector4) = 
+        
+            let v1 = Vector4(a.X + b.X, a.Y + b.Y, a.Z + b.Z, a.W + b.W)
+            let sum = Vector4.Add(a, b)
+            
+            Assert.ApproximatelyEqual(v1, sum)
+            
+        [<Property>]
+        let ``Static Vector4 addition method by reference is the same as component addition`` (a : Vector4, b : Vector4) = 
+        
+            let v1 = Vector4(a.X + b.X, a.Y + b.Y, a.Z + b.Z, a.W + b.W)
+            let sum = Vector4.Add(ref a, ref b)
+            
+            Assert.ApproximatelyEqual(v1, sum)
+            
+    [<Properties(Arbitrary = [| typeof<OpenTKGen> |])>]
+    module Subtraction = 
+        //
+        [<Property>]
+        let ``Vector4 subtraction is the same as component subtraction`` (a : Vector4, b : Vector4) = 
+            let c = a - b
+            
+            Assert.Equal(a.X - b.X,c.X)
+            Assert.Equal(a.Y - b.Y,c.Y)
+            Assert.Equal(a.Z - b.Z,c.Z)
+            Assert.Equal(a.W - b.W,c.W)
+            
+        [<Property>]
+        let ``Static Vector4 subtraction method is the same as component addition`` (a : Vector4, b : Vector4) = 
+        
+            let v1 = Vector4(a.X - b.X, a.Y - b.Y, a.Z - b.Z, a.W - b.W)
+            let sum = Vector4.Subtract(a, b)
+            
+            Assert.ApproximatelyEqual(v1, sum)
+            
+        [<Property>]
+        let ``Static Vector4 subtraction method by reference is the same as component addition`` (a : Vector4, b : Vector4) = 
+        
+            let v1 = Vector4(a.X - b.X, a.Y - b.Y, a.Z - b.Z, a.W - b.W)
+            let sum = Vector4.Subtract(ref a, ref b)
+            
+            Assert.ApproximatelyEqual(v1, sum)
+            
+    [<Properties(Arbitrary = [| typeof<OpenTKGen> |])>]
+    module Multiplication = 
+        //
+        [<Property>]
+        let ``Vector4 multiplication is the same as component multiplication`` (a : Vector4, b : Vector4) = 
+            let c = a * b
+            
+            Assert.Equal(a.X * b.X,c.X)
+            Assert.Equal(a.Y * b.Y,c.Y)
+            Assert.Equal(a.Z * b.Z,c.Z)
+            Assert.Equal(a.W * b.W,c.W)
+
+        
+        [<Property>]
+        let ``Vector4 multiplication is commutative`` (a : Vector4, b : Vector4) = 
+            let r1 = a * b
+            let r2 = b * a
+            
+            Assert.Equal(r1, r2)
+        
+        [<Property>]
+        let ``Left-handed Vector4-scalar multiplication is the same as component-scalar multiplication`` (a : Vector4, f : float32) = 
+            let r = a * f
+            
+            Assert.Equal(a.X * f,r.X)
+            Assert.Equal(a.Y * f,r.Y)
+            Assert.Equal(a.Z * f,r.Z)
+            Assert.Equal(a.W * f,r.W)
+            
+        [<Property>]
+        let ``Right-handed Vector4-scalar multiplication is the same as component-scalar multiplication`` (a : Vector4, f : float32) = 
+            let r = f * a
+            Assert.Equal(a.X * f,r.X)
+            Assert.Equal(a.Y * f,r.Y)
+            Assert.Equal(a.Z * f,r.Z)
+            Assert.Equal(a.W * f,r.W)
+            
+        [<Property>]
+        let ``Static method Vector4-scalar multiplication is the same as component-scalar multiplication`` (a : Vector4, f : float32) = 
+            let r = Vector4.Multiply(a, f)
+            
+            Assert.Equal(a.X * f,r.X)
+            Assert.Equal(a.Y * f,r.Y)
+            Assert.Equal(a.Z * f,r.Z)
+            Assert.Equal(a.W * f,r.W)
+        
+        [<Property>]
+        let ``Vector4-Matrix4 multiplication works for right-handed notation`` (a : Matrix4, b : Vector4) = 
+            let res = a*b
+            
+            let c1 = b.X * a.M11 + b.Y * a.M12 + b.Z * a.M13 + b.W * a.M14
+            let c2 = b.X * a.M21 + b.Y * a.M22 + b.Z * a.M23 + b.W * a.M24
+            let c3 = b.X * a.M31 + b.Y * a.M32 + b.Z * a.M33 + b.W * a.M34
+            let c4 = b.X * a.M41 + b.Y * a.M42 + b.Z * a.M43 + b.W * a.M44
+            
+            let exp = Vector4(c1, c2, c3, c4)
+            
+            Assert.Equal(exp, res)
+            
+        [<Property>]
+        let ``Vector4-Matrix4 multiplication works for left-handed notation`` (a : Matrix4, b : Vector4) = 
+            let res = b*a
+            
+            let c1 = b.X * a.M11 + b.Y * a.M21 + b.Z * a.M31 + b.W * a.M41
+            let c2 = b.X * a.M12 + b.Y * a.M22 + b.Z * a.M32 + b.W * a.M42
+            let c3 = b.X * a.M13 + b.Y * a.M23 + b.Z * a.M33 + b.W * a.M43
+            let c4 = b.X * a.M14 + b.Y * a.M24 + b.Z * a.M34 + b.W * a.M44
+            
+            let exp = Vector4(c1, c2, c3, c4)
+            
+            Assert.Equal(exp, res)
+            
+        [<Property>]
+        let ``Static Vector4 multiplication method is the same as component multiplication`` (a : Vector4, b : Vector4) = 
+        
+            let v1 = Vector4(a.X * b.X, a.Y * b.Y, a.Z * b.Z, a.W * b.W)
+            let sum = Vector4.Multiply(a, b)
+            
+            Assert.ApproximatelyEqual(v1, sum)
+            
+        [<Property>]
+        let ``Static Vector4 multiplication method by reference is the same as component multiplication`` (a : Vector4, b : Vector4) = 
+        
+            let v1 = Vector4(a.X * b.X, a.Y * b.Y, a.Z * b.Z, a.W * b.W)
+            let sum = Vector4.Multiply(ref a, ref b)
+            
+            Assert.ApproximatelyEqual(v1, sum)
+                    
+    [<Properties(Arbitrary = [| typeof<OpenTKGen> |])>]
+    module Division = 
+        //
+        [<Property>]
+        let ``Vector4-float division is the same as component-float division`` (a : Vector4, f : float32) = 
+            if not (approxEq f 0.0f) then // we don't support diving by zero.
+                let r = a / f
+                
+                Assert.ApproximatelyEqual(a.X / f, r.X)
+                Assert.ApproximatelyEqual(a.Y / f, r.Y)
+                Assert.ApproximatelyEqual(a.Z / f, r.Z)
+                Assert.ApproximatelyEqual(a.W / f, r.W)
+                
+        [<Property>]
+        let ``Static Vector4-Vector4 division method works`` (a : Vector4, b : Vector4) = 
+        
+            let v1 = Vector4(a.X / b.X, a.Y / b.Y, a.Z / b.Z, a.W / b.W)
+            let sum = Vector4.Divide(a, b)
+            
+            Assert.ApproximatelyEqual(v1, sum)
+            
+        [<Property>]
+        let ``Static Vector4-Vector4 divison method works by reference`` (a : Vector4, b : Vector4) = 
+        
+            let v1 = Vector4(a.X / b.X, a.Y / b.Y, a.Z / b.Z, a.W / b.W)
+            let sum = Vector4.Divide(ref a, ref b)
+            
+            Assert.ApproximatelyEqual(v1, sum)
+            
+        [<Property>]
+        let ``Static Vector4-scalar division method works`` (a : Vector4, b : float32) = 
+        
+            let v1 = Vector4(a.X / b, a.Y / b, a.Z / b, a.W / b)
+            let sum = Vector4.Divide(a, b)
+            
+            Assert.ApproximatelyEqual(v1, sum)
+            
+        [<Property>]
+        let ``Static Vector4-scalar divison method works by reference`` (a : Vector4, b : float32) = 
+        
+            let v1 = Vector4(a.X / b, a.Y / b, a.Z / b, a.W / b)
+            let sum = Vector4.Divide(ref a, b)
+            
+            Assert.ApproximatelyEqual(v1, sum)
+                
+    [<Properties(Arbitrary = [| typeof<OpenTKGen> |])>]
+    module Negation =
+        //
+        [<Property>]
+        let ``Vector negation operator works`` (x, y, z, w) =
+            let v = Vector4(x, y, z, w)
+            let vNeg = -v
+            Assert.Equal(-x, vNeg.X)
+            Assert.Equal(-y, vNeg.Y)
+            Assert.Equal(-z, vNeg.Z)
+            Assert.Equal(-w, vNeg.W)
+            
+    [<Properties(Arbitrary = [| typeof<OpenTKGen> |])>]
+    module Equality =
+        //
+        [<Property>]
+        let ``Vector equality operator works`` (x, y, z, w) =
+            let v1 = Vector4(x, y, z, w)
+            let v2 = Vector4(x, y, z, w)
+            let equality = v1 = v2
+            
+            Assert.True(equality)
+            
+        [<Property>]
+        let ``Vector inequality operator works`` (x, y, z, w) =
+            let v1 = Vector4(x, y, z, w)
+            let v2 = Vector4(x + (float32)1 , y + (float32)1, z + (float32)1, w + (float32)1)
+            let inequality = v1 <> v2
+            
+            Assert.True(inequality)
+            
+        [<Property>]
+        let ``Vector equality method works`` (x, y, z, w) =
+            let v1 = Vector4(x, y, z, w)
+            let v2 = Vector4(x, y, z, w)
+            let notVector = Matrix2()
+            
+            let equality = v1.Equals(v2)
+            let inequalityByOtherType = v1.Equals(notVector)
+            
+            Assert.True(equality)
+            Assert.False(inequalityByOtherType)
+            
+    [<Properties(Arbitrary = [| typeof<OpenTKGen> |])>]
+    module Swizzling =
+        //
+        [<Property>]
+        let ``Vector swizzling works for X-primary components`` (x, y, z, w) =
+        
+            let v = Vector4(x, y, z, w)
+            
+            let xyzw = v
+            let xywz = Vector4(x, y, w, z)
+            let xzyw = Vector4(x, z, y, w)
+            let xzwy = Vector4(x, z, w, y)
+            let xwyz = Vector4(x, w, y, z)
+            let xwzy = Vector4(x, w, z, y)
+            
+            let xyz = Vector3(x, y, z)
+            let xyw = Vector3(x, y, w)
+            let xzy = Vector3(x, z, y)
+            let xzw = Vector3(x, z, w)
+            let xwy = Vector3(x, w, y)
+            let xwz = Vector3(x, w, z)
+            
+            let xy = Vector2(x, y)
+            let xz = Vector2(x, z)
+            let xw = Vector2(x, w)
+            
+            // X primary
+            Assert.Equal(xyzw, v)
+            Assert.Equal(xywz, v.Xywz)
+            Assert.Equal(xzyw, v.Xzyw)
+            Assert.Equal(xzwy, v.Xzwy)
+            Assert.Equal(xwyz, v.Xwyz)
+            Assert.Equal(xwzy, v.Xwzy)
+            
+            Assert.Equal(xyz, v.Xyz)
+            Assert.Equal(xyw, v.Xyw)
+            Assert.Equal(xzy, v.Xzy)
+            Assert.Equal(xzw, v.Xzw)
+            Assert.Equal(xwy, v.Xwy)
+            Assert.Equal(xwz, v.Xwz)
+            
+            Assert.Equal(xy, v.Xy)
+            Assert.Equal(xz, v.Xz)
+            Assert.Equal(xw, v.Xw)
+            
+        [<Property>]
+        let ``Vector swizzling works for Y-primary components`` (x, y, z, w) =
+        
+            let v = Vector4(x, y, z, w)
+            
+            let yxzw = Vector4(y, x, z, w)
+            let yxwz = Vector4(y, x, w, z)
+            let yyzw = Vector4(y, y, z, w)
+            let yywz = Vector4(y, y, w, z)
+            let yzxw = Vector4(y, z, x, w)
+            let yzwx = Vector4(y, z, w, x)
+            let ywxz = Vector4(y, w, x, z)
+            let ywzx = Vector4(y, w, z, x)
+            
+            let yxz = Vector3(y, x, z)
+            let yxw = Vector3(y, x, w)
+            let yzx = Vector3(y, z, x)
+            let yzw = Vector3(y, z, w)
+            let ywx = Vector3(y, w, x)
+            let ywz = Vector3(y, w, z)
+            
+            let yx = Vector2(y, x)
+            let yz = Vector2(y, z)
+            let yw = Vector2(y, w)
+            
+            // Y primary
+            Assert.Equal(yxzw, v.Yxzw)
+            Assert.Equal(yxwz, v.Yxwz)
+            Assert.Equal(yyzw, v.Yyzw)
+            Assert.Equal(yywz, v.Yywz)
+            Assert.Equal(yzxw, v.Yzxw)
+            Assert.Equal(yzwx, v.Yzwx)
+            Assert.Equal(ywxz, v.Ywxz)
+            Assert.Equal(ywzx, v.Ywzx)
+            
+            Assert.Equal(yxz, v.Yxz)
+            Assert.Equal(yxw, v.Yxw)
+            Assert.Equal(yzx, v.Yzx)
+            Assert.Equal(yzw, v.Yzw)
+            Assert.Equal(ywx, v.Ywx)
+            Assert.Equal(ywz, v.Ywz)
+            
+            Assert.Equal(yx, v.Yx)
+            Assert.Equal(yz, v.Yz)
+            Assert.Equal(yw, v.Yw)
+            
+        [<Property>]
+        let ``Vector swizzling works for Z-primary components`` (x, y, z, w) =
+        
+            let v = Vector4(x, y, z, w)
+            
+            let zxyw = Vector4(z, x, y, w)
+            let zxwy = Vector4(z, x, w, y)
+            let zyxw = Vector4(z, y, x, w)
+            let zywx = Vector4(z, y, w, x)
+            let zwxy = Vector4(z, w, x, y)
+            let zwyx = Vector4(z, w, y, x)
+            let zwzy = Vector4(z, w, z, y)
+            
+            let zxy = Vector3(z, x, y)
+            let zxw = Vector3(z, x, w)
+            let zyx = Vector3(z, y, x)
+            let zyw = Vector3(z, y, w)
+            let zwx = Vector3(z, w, x)
+            let zwy = Vector3(z, w, y)
+            
+            let zx = Vector2(z, x)
+            let zy = Vector2(z, y)
+            let zw = Vector2(z, w)
+            
+            // Z primary
+            Assert.Equal(zxyw, v.Zxyw)
+            Assert.Equal(zxwy, v.Zxwy)
+            Assert.Equal(zyxw, v.Zyxw)
+            Assert.Equal(zywx, v.Zywx)
+            Assert.Equal(zwxy, v.Zwxy)
+            Assert.Equal(zwyx, v.Zwyx)
+            Assert.Equal(zwzy, v.Zwzy)
+            
+            Assert.Equal(zxy, v.Zxy)
+            Assert.Equal(zxw, v.Zxw)
+            Assert.Equal(zyx, v.Zyx)
+            Assert.Equal(zyw, v.Zyw)
+            Assert.Equal(zwx, v.Zwx)
+            Assert.Equal(zwy, v.Zwy)
+            
+            Assert.Equal(zx, v.Zx)
+            Assert.Equal(zy, v.Zy)
+            Assert.Equal(zw, v.Zw)
+        
+        [<Property>]
+        let ``Vector swizzling works for W-primary components`` (x, y, z, w) =
+        
+            let v = Vector4(x, y, z, w)
+
+            let wxyz = Vector4(w, x, y, z)
+            let wxzy = Vector4(w, x, z, y)
+            let wyxz = Vector4(w, y, x, z)
+            let wyzx = Vector4(w, y, z, x)
+            let wzxy = Vector4(w, z, x, y)
+            let wzyx = Vector4(w, z, y, x)
+            let wzyw = Vector4(w, z, y, w)
+            
+            let wxy = Vector3(w, x, y)
+            let wxz = Vector3(w, x, z)
+            let wyx = Vector3(w, y, x)
+            let wyz = Vector3(w, y, z)
+            let wzx = Vector3(w, z, x)
+            let wzy = Vector3(w, z, y)
+            
+            let wx = Vector2(w, x)
+            let wy = Vector2(w, y)
+            let wz = Vector2(w, z)
+
+            // W primary
+            Assert.Equal(wxyz, v.Wxyz)
+            Assert.Equal(wxzy, v.Wxzy)
+            Assert.Equal(wyxz, v.Wyxz)
+            Assert.Equal(wyzx, v.Wyzx)
+            Assert.Equal(wzxy, v.Wzxy)
+            Assert.Equal(wzyx, v.Wzyx)
+            Assert.Equal(wzyw, v.Wzyw)
+            
+            Assert.Equal(wxy, v.Wxy)
+            Assert.Equal(wxz, v.Wxz)
+            Assert.Equal(wyx, v.Wyx)
+            Assert.Equal(wyz, v.Wyz)
+            Assert.Equal(wzx, v.Wzx)
+            Assert.Equal(wzy, v.Wzy)
+            
+            Assert.Equal(wx, v.Wx)
+            Assert.Equal(wy, v.Wy)
+            Assert.Equal(wz, v.Wz)
+            
+    [<Properties(Arbitrary = [| typeof<OpenTKGen> |])>]
+    module Interpolation =
+        //
+        [<Property>]
+        let ``Linear interpolation works`` (a : Vector4, b : Vector4, q) =
+
+            let blend = q
+            
+            let rX = blend * (b.X - a.X) + a.X 
+            let rY = blend * (b.Y - a.Y) + a.Y
+            let rZ = blend * (b.Z - a.Z) + a.Z
+            let rW = blend * (b.W - a.W) + a.W
+            let vExp = Vector4(rX, rY, rZ, rW)
+            
+            Assert.Equal(vExp, Vector4.Lerp(a, b, q))
+            
+            let vRes = Vector4.Lerp(ref a, ref b, q)
+            Assert.Equal(vExp, vRes)
+            
+        [<Property>]
+        let ``Barycentric interpolation works`` (a : Vector4, b : Vector4, c : Vector4, u, v) =
+
+            let r = a + u * (b - a) + v * (c - a)
+            
+            Assert.Equal(r, Vector4.BaryCentric(a, b, c, u, v))
+            
+            let vRes = Vector4.BaryCentric(ref a, ref b, ref c, u, v)
+            Assert.Equal(r, vRes)
+            
+    [<Properties(Arbitrary = [| typeof<OpenTKGen> |])>]
+    module ``Vector products`` =
+        //
+        [<Property>]
+        let ``Dot product works`` (a : Vector4, b : Vector4) =
+            let dot = a.X * b.X + a.Y * b.Y + a.Z * b.Z + a.W * b.W
+            
+            Assert.Equal(dot, Vector4.Dot(a, b));
+            
+            let vRes = Vector4.Dot(ref a, ref b)
+            Assert.Equal(dot, vRes)
+            
+    [<Properties(Arbitrary = [| typeof<OpenTKGen> |])>]
+    module ``Component min and max`` =
+        //
+        [<Property>]
+        let ``Selecting the lesser of two vectors works`` (x, y, z, w, a, b, c, d) =
+            let v1 = Vector4(x, y, z, w)
+            let v2 = Vector4(a, b, c, d)
+            
+            let l1 = v1.LengthSquared
+            let l2 = v2.LengthSquared
+            
+            let vMin = Vector4.Min(v1, v2)
+            
+            if vMin = v1 then
+                let v1ShorterThanv2 = l1 < l2
+                Assert.True(v1ShorterThanv2)
+            else 
+                let v2ShorterThanv1 = l2 < l1
+                Assert.True(v2ShorterThanv1) 
+            
+        [<Property>]
+        let ``Selecting the greater of two vectors works`` (x, y, z, w, a, b, c, d) =
+            let v1 = Vector4(x, y, z, w)
+            let v2 = Vector4(a, b, c, d)
+            
+            let l1 = v1.LengthSquared
+            let l2 = v2.LengthSquared
+            
+            let vMin = Vector4.Max(v1, v2)
+            
+            if vMin = v1 then
+                let v1LongerThanOrEqualTov2 = l1 >= l2 
+                Assert.True(v1LongerThanOrEqualTov2)
+            else 
+                let v2LongerThanv1 = l2 > l1 
+                Assert.True(v2LongerThanv1) 
+                
+    [<Properties(Arbitrary = [| typeof<OpenTKGen> |])>]
+    module Clamping =
+        //
+        [<Property>]
+        let ``Clamping one vector between two other vectors works`` (a : Vector4, b : Vector4, w : Vector4) =
+            let res = Vector4.Clamp(w, a, b)
+            
+            let expX = if w.X < a.X then a.X else if w.X > b.X then b.X else w.X
+            let expY = if w.Y < a.Y then a.Y else if w.Y > b.Y then b.Y else w.Y
+            let expZ = if w.Z < a.Z then a.Z else if w.Z > b.Z then b.Z else w.Z
+            let expW = if w.W < a.W then a.W else if w.W > b.W then b.W else w.W
+            
+            Assert.Equal(expX, res.X)
+            Assert.Equal(expY, res.Y)
+            Assert.Equal(expZ, res.Z)
+            Assert.Equal(expW, res.W)
+            
+        [<Property>]
+        let ``Clamping one vector between two other vectors works by reference`` (a : Vector4, b : Vector4, w : Vector4) =
+            let res = Vector4.Clamp(ref w, ref a, ref b)
+            
+            let expX = if w.X < a.X then a.X else if w.X > b.X then b.X else w.X
+            let expY = if w.Y < a.Y then a.Y else if w.Y > b.Y then b.Y else w.Y
+            let expZ = if w.Z < a.Z then a.Z else if w.Z > b.Z then b.Z else w.Z
+            let expW = if w.W < a.W then a.W else if w.W > b.W then b.W else w.W
+            
+            Assert.Equal(expX, res.X)
+            Assert.Equal(expY, res.Y)
+            Assert.Equal(expZ, res.Z)
+            Assert.Equal(expW, res.W)
+            
+    [<Properties(Arbitrary = [| typeof<OpenTKGen> |])>]
+    module ``Unit vectors``= 
+        //
+        [<Property>]
+        let ``Unit X is correct``  = 
+            let unitX = Vector4((float32)1, (float32)0, (float32)0, (float32)0)
+            
+            Assert.Equal(Vector4.UnitX, unitX)
+            
+        [<Property>]
+        let ``Unit Y is correct``  = 
+            let unitY = Vector4((float32)0, (float32)1, (float32)0, (float32)0)
+            
+            Assert.Equal(Vector4.UnitY, unitY)
+            
+        [<Property>]
+        let ``Unit Z is correct``  = 
+            let unitZ = Vector4((float32)0, (float32)0, (float32)1, (float32)0)
+            
+            Assert.Equal(Vector4.UnitZ, unitZ)
+            
+        [<Property>]
+        let ``Unit W is correct``  = 
+            let unitW = Vector4((float32)0, (float32)0, (float32)0, (float32)1)
+            
+            Assert.Equal(Vector4.UnitW, unitW)
+        
+        [<Property>]
+        let ``Unit zero is correct``  = 
+            let unitZero = Vector4((float32)0, (float32)0, (float32)0, (float32)0)
+            
+            Assert.Equal(Vector4.Zero, unitZero)
+            
+        [<Property>]
+        let ``Unit one is correct``  = 
+            let unitOne = Vector4((float32)1, (float32)1, (float32)1, (float32)1)
+            
+            Assert.Equal(Vector4.One, unitOne)
+            
+    [<Properties(Arbitrary = [| typeof<OpenTKGen> |])>]
+    module Serialization = 
+        //
+        [<Property>]
+        let ``The absolute size of a Vector4 is always the size of its components`` (v : Vector4) = 
+            let expectedSize = sizeof<float32> * 4
+            
+            Assert.Equal(expectedSize, Vector4.SizeInBytes)
+            Assert.Equal(expectedSize, Marshal.SizeOf(Vector4()))
\ No newline at end of file