diff --git a/tests/OpenTK.Tests.Math/QuaternionTests.cs b/tests/OpenTK.Tests.Math/QuaternionTests.cs
index 3db06f30..1f078d32 100644
--- a/tests/OpenTK.Tests.Math/QuaternionTests.cs
+++ b/tests/OpenTK.Tests.Math/QuaternionTests.cs
@@ -7,121 +7,152 @@ namespace OpenTK.Tests.Math
 	public class Quaternion_Tests
 	{
 		/// <summary>
-		/// Checks if a single given value (either pitch, yaw or roll) get converted into correct x,y,z value of quaternion.
+		/// Contains all tests which cover the ctor of Quaternion.
 		/// </summary>
-		/// <param name="eulerValues">euler angle values</param>
-		/// <param name="expectedResult">expected xyz component of quaternion</param>
-		/// <param name="testName">Taken from nUnit test data. Don't know how to name data driven tests for xUnit which actually works.</param>
-		[Theory]
-		[MemberData(nameof(QuaternionTestDataGenerator.SingleAxisTestCases), MemberType = typeof(QuaternionTestDataGenerator))]
-		public void CtorEulerAnglesFloat_SingleEulerAngleSet_RotateCorrectAxis(Vector3 eulerValues, Vector3 expectedResult, string testName)
+		public class Constructor_Tests
 		{
-			//Arrange + Act: Create Quaternion with "pitch/yaw/roll"
-			var cut = new Quaternion(eulerValues.X, eulerValues.Y, eulerValues.Z);
+			/// <summary>
+			/// Checks if a single given value (either pitch, yaw or roll) get converted into correct x,y,z value of quaternion.
+			/// </summary>
+			/// <param name="eulerValues">euler angle values</param>
+			/// <param name="expectedResult">expected xyz component of quaternion</param>
+			/// <param name="testName">Taken from nUnit test data. Don't know how to name data driven tests for xUnit which actually works.</param>
+			[Theory]
+			[MemberData(nameof(QuaternionTestDataGenerator.SingleAxisTestCases), MemberType = typeof(QuaternionTestDataGenerator))]
+			public void SingleAxisAsEulerAnglesInFloatsIsConvertedToCorrectValueInQuaternion
+			(Vector3 eulerValues, Vector3 expectedResult, string testName)
+			{
+				//Arrange + Act: Create Quaternion with "pitch/yaw/roll"
+				var cut = new Quaternion(eulerValues.X, eulerValues.Y, eulerValues.Z);
 
-			//Assert: Use helper, to check if part of the two correct axis is zero. I just want check the direction
-			Vector3 resultXYZ = cut.Xyz;
+				//Assert: Use helper, to check if part of the two correct axis is zero. I just want check the direction
+				Vector3 resultXYZ = cut.Xyz;
 
-			Assert.True(QuaternionTestHelper.VerifyEqualSingleDirection(resultXYZ, expectedResult));
+				Assert.True(QuaternionTestHelper.VerifyEqualSingleDirection(resultXYZ, expectedResult));
+			}
+
+			/// <summary>
+			/// Checks if a single given value (either pitch, yaw or roll) get converted into correct x,y,z value of quaternion.
+			/// </summary>
+			/// <param name="eulerValues">euler angle values</param>
+			/// <param name="expectedResult">expected xyz component of quaternion</param>
+			/// <param name="testName">Taken from nUnit test data. Don't know how to name data driven tests for xUnit which actually works.</param>
+			[Theory]
+			[MemberData(nameof(QuaternionTestDataGenerator.SingleAxisTestCases), MemberType = typeof(QuaternionTestDataGenerator))]
+			public void SingleAxisAsEulerAnglesInVector3IsConvertedToCorrectValueInQuaternion
+			(Vector3 eulerValues, Vector3 expectedResult, string testName)
+			{
+				//Arrange + Act: Create Quaternion with "pitch/yaw/roll"
+				var cut = new Quaternion(eulerValues);
+
+				//Assert: Use helper, to check if part of the two correct axis is zero. I just want check the direction
+				Vector3 resultXYZ = cut.Xyz;
+
+				Assert.True(QuaternionTestHelper.VerifyEqualSingleDirection(resultXYZ, expectedResult));
+			}
+
+			//TODO: Make also checks with ccw rotation angle and correct applied rotation order of multiple axis
 		}
 
 		/// <summary>
-		/// Checks if a single given value (either pitch, yaw or roll) get converted into correct x,y,z value of quaternion.
+		/// Contains all tests for FromEulerAngles
 		/// </summary>
-		/// <param name="eulerValues">euler angle values</param>
-		/// <param name="expectedResult">expected xyz component of quaternion</param>
-		/// <param name="testName">Taken from nUnit test data. Don't know how to name data driven tests for xUnit which actually works.</param>
-		[Theory]
-		[MemberData(nameof(QuaternionTestDataGenerator.SingleAxisTestCases), MemberType = typeof(QuaternionTestDataGenerator))]
-		public void CtorEulerAnglesVector3_SingleEulerAngleSet_RotateCorrectAxis(Vector3 eulerValues, Vector3 expectedResult, string testName)
+		public class FromEulerAngles_Tests
 		{
-			//Arrange + Act: Create Quaternion with "pitch/yaw/roll"
-			var cut = new Quaternion(eulerValues);
+			/// <summary>
+			/// Checks if a single given value (either pitch, yaw or roll) get converted into correct x,y,z value of quaternion.
+			/// </summary>
+			/// <param name="eulerValues">euler angle values</param>
+			/// <param name="expectedResult">expected xyz component of quaternion</param>
+			/// <param name="testName">Taken from nUnit test data. Don't know how to name data driven tests for xUnit which actually works.</param>
+			[Theory]
+			[MemberData(nameof(QuaternionTestDataGenerator.SingleAxisTestCases), MemberType = typeof(QuaternionTestDataGenerator))]
+			public void SingleAxisAsEulerAnglesInFloatsIsConvertedToCorrectValueInQuaternion
+			(Vector3 eulerValues, Vector3 expectedResult, string testName)
+			{
+				//Arrange + Act: Create Quaternion with "pitch/yaw/roll"
+				var cut = Quaternion.FromEulerAngles(eulerValues.X, eulerValues.Y, eulerValues.Z);
 
-			//Assert: Use helper, to check if part of the two correct axis is zero. I just want check the direction
-			Vector3 resultXYZ = cut.Xyz;
+				//Assert: Use helper, to check if part of the two correct axis is zero. I just want check the direction
+				Vector3 resultXYZ = cut.Xyz;
 
-			Assert.True(QuaternionTestHelper.VerifyEqualSingleDirection(resultXYZ, expectedResult));
+				Assert.True(QuaternionTestHelper.VerifyEqualSingleDirection(resultXYZ, expectedResult));
+			}
+
+			/// <summary>
+			/// Checks if a single given value (either pitch, yaw or roll) get converted into correct x,y,z value of quaternion.
+			/// </summary>
+			/// <param name="eulerValues">euler angle values</param>
+			/// <param name="expectedResult">expected xyz component of quaternion</param>
+			/// <param name="testName">Taken from nUnit test data. Don't know how to name data driven tests for xUnit which actually works.</param>
+			[Theory]
+			[MemberData(nameof(QuaternionTestDataGenerator.SingleAxisTestCases), MemberType = typeof(QuaternionTestDataGenerator))]
+			public void SingleAxisAsEulerAnglesInVector3IsConvertedToCorrectValueInQuaternion
+			(Vector3 eulerValues, Vector3 expectedResult, string testName)
+			{
+				//Arrange + Act: Create Quaternion with "pitch/yaw/roll"
+				var cut = Quaternion.FromEulerAngles(eulerValues);
+
+				//Assert: Use helper, to check if part of the two correct axis is zero. I just want check the direction
+				Vector3 resultXYZ = cut.Xyz;
+
+				Assert.True(QuaternionTestHelper.VerifyEqualSingleDirection(resultXYZ, expectedResult));
+			}
+
+			/// <summary>
+			/// Checks if a single given value (either pitch, yaw or roll) get converted into correct x,y,z value of quaternion.
+			/// </summary>
+			/// <param name="eulerValues">euler angle values</param>
+			/// <param name="expectedResult">expected xyz component of quaternion</param>
+			/// <param name="testName">Taken from nUnit test data. Don't know how to name data driven tests for xUnit which actually works.</param>
+			[Theory]
+			[MemberData(nameof(QuaternionTestDataGenerator.SingleAxisTestCases), MemberType = typeof(QuaternionTestDataGenerator))]
+			public void SingleAxisAsEulerAnglesInVector3IsConvertedToCorrectValueInQuaternionAsOutParam
+			(Vector3 eulerValues, Vector3 expectedResult, string testName)
+			{
+				//Arrange + Act: Create Quaternion with "pitch/yaw/roll"
+				var cut = Quaternion.Identity;
+				Quaternion.FromEulerAngles(ref eulerValues, out cut);
+
+				//Assert: Use helper, to check if part of the two correct axis is zero. I just want check the direction
+				Vector3 resultXYZ = cut.Xyz;
+
+				Assert.True(QuaternionTestHelper.VerifyEqualSingleDirection(resultXYZ, expectedResult));
+			}
+
+			//TODO: Make also checks with ccw rotation angle and correct applied rotation order of multiple axis
 		}
 
+
 		/// <summary>
-		/// Checks if a single given value (either pitch, yaw or roll) get converted into correct x,y,z value of quaternion.
+		/// Contains all test for ToAxisAngle
 		/// </summary>
-		/// <param name="eulerValues">euler angle values</param>
-		/// <param name="expectedResult">expected xyz component of quaternion</param>
-		/// <param name="testName">Taken from nUnit test data. Don't know how to name data driven tests for xUnit which actually works.</param>
-		[Theory]
-		[MemberData(nameof(QuaternionTestDataGenerator.SingleAxisTestCases), MemberType = typeof(QuaternionTestDataGenerator))]
-		public void FromEulerAnglesFloat_SingleEulerAngleSet_RotateCorrectAxis(Vector3 eulerValues, Vector3 expectedResult, string testName)
+		public class ToAxisAngle
 		{
-			//Arrange + Act: Create Quaternion with "pitch/yaw/roll"
-			var cut = Quaternion.FromEulerAngles(eulerValues.X, eulerValues.Y, eulerValues.Z);
+			/// <summary>
+			/// Check if a quaternion returns a a rotation about the correct coordinate axis
+			/// </summary>
+			/// <param name="cut">Prepared Quaternion</param>
+			/// <param name="expectedResult">Expected result.</param>
+			/// <param name="testName">Taken from nUnit test data. Don't know how to name data driven tests for xUnit which actually works.</param>
+			[Theory]
+			[MemberData(nameof(QuaternionTestDataGenerator.ToAxisAngleTestCases), MemberType = typeof(QuaternionTestDataGenerator))]
+			public void PreparedSingleRotationAxisQuaternionConvertsToCorrectAxisAngleRepresentation(Quaternion cut, Vector3 expectedResult, string testName)
+			{
+				//Arrange + Act: Create Quaternion with rotation about X/Y/Z axis
+				Vector3 resultXYZ;
+				float dontCare;
+				cut.ToAxisAngle(out resultXYZ, out dontCare);
 
-			//Assert: Use helper, to check if part of the two correct axis is zero. I just want check the direction
-			Vector3 resultXYZ = cut.Xyz;
+				//Assert: Use helper, to check if part of the two correct axis is zero. I just want check the direction
+				Assert.True(QuaternionTestHelper.VerifyEqualSingleDirection(resultXYZ, expectedResult));
+			}
 
-			Assert.True(QuaternionTestHelper.VerifyEqualSingleDirection(resultXYZ, expectedResult));
+			//TODO: Make also checks with ccw rotation angle and correct applied rotation order of multiple axis
 		}
 
-		/// <summary>
-		/// Checks if a single given value (either pitch, yaw or roll) get converted into correct x,y,z value of quaternion.
-		/// </summary>
-		/// <param name="eulerValues">euler angle values</param>
-		/// <param name="expectedResult">expected xyz component of quaternion</param>
-		/// <param name="testName">Taken from nUnit test data. Don't know how to name data driven tests for xUnit which actually works.</param>
-		[Theory]
-		[MemberData(nameof(QuaternionTestDataGenerator.SingleAxisTestCases), MemberType = typeof(QuaternionTestDataGenerator))]
-		public void FromEulerAnglesVector3_SingleEulerAngleSet_RotateCorrectAxis(Vector3 eulerValues, Vector3 expectedResult, string testName)
-		{
-			//Arrange + Act: Create Quaternion with "pitch/yaw/roll"
-			var cut = Quaternion.FromEulerAngles(eulerValues);
 
-			//Assert: Use helper, to check if part of the two correct axis is zero. I just want check the direction
-			Vector3 resultXYZ = cut.Xyz;
 
-			Assert.True(QuaternionTestHelper.VerifyEqualSingleDirection(resultXYZ, expectedResult));
-		}
-
-		/// <summary>
-		/// Checks if a single given value (either pitch, yaw or roll) get converted into correct x,y,z value of quaternion.
-		/// </summary>
-		/// <param name="eulerValues">euler angle values</param>
-		/// <param name="expectedResult">expected xyz component of quaternion</param>
-		/// <param name="testName">Taken from nUnit test data. Don't know how to name data driven tests for xUnit which actually works.</param>
-		[Theory]
-		[MemberData(nameof(QuaternionTestDataGenerator.SingleAxisTestCases), MemberType = typeof(QuaternionTestDataGenerator))]
-		public void FromEulerAnglesOut_SingleEulerAngleSet_RotateCorrectAxis(Vector3 eulerValues, Vector3 expectedResult, string testName)
-		{
-			//Arrange + Act: Create Quaternion with "pitch/yaw/roll"
-			var cut = Quaternion.Identity;
-			Quaternion.FromEulerAngles(ref eulerValues, out cut);
-
-			//Assert: Use helper, to check if part of the two correct axis is zero. I just want check the direction
-			Vector3 resultXYZ = cut.Xyz;
-
-			Assert.True(QuaternionTestHelper.VerifyEqualSingleDirection(resultXYZ, expectedResult));
-		}
-
-		/// <summary>
-		/// Check if a quaternion returns a a rotation about the correct coordinate axis
-		/// </summary>
-		/// <param name="cut">Prepared Quaternion</param>
-		/// <param name="expectedResult">Expected result.</param>
-		/// <param name="testName">Taken from nUnit test data. Don't know how to name data driven tests for xUnit which actually works.</param>
-		[Theory]
-		[MemberData(nameof(QuaternionTestDataGenerator.ToAxisAngleTestCases), MemberType = typeof(QuaternionTestDataGenerator))]
-		public void ToAxisAngle_SingleAxisSetAndAngleIgnored_RotateCorrectAxis(Quaternion cut, Vector3 expectedResult, string testName)
-		{
-			//Arrange + Act: Create Quaternion with rotation about X/Y/Z axis
-			Vector3 resultXYZ;
-			float dontCare;
-			cut.ToAxisAngle(out resultXYZ, out dontCare);
-
-			//Assert: Use helper, to check if part of the two correct axis is zero. I just want check the direction
-			Assert.True(QuaternionTestHelper.VerifyEqualSingleDirection(resultXYZ, expectedResult));
-		}
-
-		//TODO: Make also checks with rotation angle
 	}
 }