[Test]
public void CreateBoundingBoxFromMinAndMax()
{
    var boundingBox = new BoundingBox(Vector3D.Zero, Vector3D.One);
    Assert.AreEqual(Vector3D.Zero, boundingBox.Min);
    Assert.AreEqual(Vector3D.One, boundingBox.Max);
}

[Test]
public void CreateBoundingBoxFromMinAndMax()
{
    var boundingBox = new BoundingBox(Vector3D.Zero, Vector3D.One);
    Assert.AreEqual(Vector3D.Zero, boundingBox.Min);
    Assert.AreEqual(Vector3D.One, boundingBox.Max);
}

[Test]
public void CreateBoundingBoxFromCenter()
{
    var box = BoundingBox.FromCenter(Vector3D.Zero, Vector3D.One);
    Assert.AreEqual(-Vector3D.One / 2, box.Min);
    Assert.AreEqual(Vector3D.One / 2, box.Max);
}

[Test]
public void CreateBoundingBoxFromCenter()
{
    var box = BoundingBox.FromCenter(Vector3D.Zero, Vector3D.One);
    Assert.AreEqual(-Vector3D.One / 2, box.Min);
    Assert.AreEqual(Vector3D.One / 2, box.Max);
}

[Test]
public void CreateBoundingBoxByPoints()
{
    Assert.Throws<BoundingBox.NoPointsSpecified>(() => new BoundingBox(null));
    Assert.Throws<BoundingBox.NoPointsSpecified>(() => new BoundingBox(new Vector3D[0]));
    var points = new[] { new Vector3D(2, 5, 7), new Vector3D(6, 4, 2), new Vector3D(1, 7, 9), };
    var boundingBox = new BoundingBox(points);
    Assert.AreEqual(boundingBox.Min, new Vector3D(1, 4, 2));
    Assert.AreEqual(boundingBox.Max, new Vector3D(6, 7, 9));
}

[Test]
public void CreateBoundingBoxByPoints()
{
    Assert.Throws<BoundingBox.NoPointsSpecified>(() => new BoundingBox(null));
    Assert.Throws<BoundingBox.NoPointsSpecified>(() => new BoundingBox(new Vector3D[0]));
    var points = new[] { new Vector3D(2, 5, 7), new Vector3D(6, 4, 2), new Vector3D(1, 7, 9), };
    var boundingBox = new BoundingBox(points);
    Assert.AreEqual(boundingBox.Min, new Vector3D(1, 4, 2));
    Assert.AreEqual(boundingBox.Max, new Vector3D(6, 7, 9));
}

[Test]
public void CheckForExactEquality()
{
    var box = new BoundingBox(Vector3D.Zero, Vector3D.One);
    var equalBox = new BoundingBox(Vector3D.Zero, Vector3D.One);
    Assert.IsTrue(box.Equals((object)equalBox));
}

[Test]
public void CheckForExactEquality()
{
    var box = new BoundingBox(Vector3D.Zero, Vector3D.One);
    var equalBox = new BoundingBox(Vector3D.Zero, Vector3D.One);
    Assert.IsTrue(box.Equals((object)equalBox));
}

[Test]
public void GetHashCodeViaDictionary()
{
    var box = new BoundingBox(Vector3D.Zero, Vector3D.One);
    var equalBox = new BoundingBox(Vector3D.Zero, Vector3D.One);
    Assert.AreEqual(box.GetHashCode(), equalBox.GetHashCode());
    var otherBox = new BoundingBox(-Vector3D.One, Vector3D.One);
    Assert.AreNotEqual(box.GetHashCode(), otherBox.GetHashCode());
}

[Test]
public void GetHashCodeViaDictionary()
{
    var box = new BoundingBox(Vector3D.Zero, Vector3D.One);
    var equalBox = new BoundingBox(Vector3D.Zero, Vector3D.One);
    Assert.AreEqual(box.GetHashCode(), equalBox.GetHashCode());
    var otherBox = new BoundingBox(-Vector3D.One, Vector3D.One);
    Assert.AreNotEqual(box.GetHashCode(), otherBox.GetHashCode());
}

[Test]
public void CheckForNearlyEqual()
{
    var boxMaximum = Vector3D.One;
    var box = new BoundingBox(Vector3D.Zero, boxMaximum);
    const float AllowedValueEpsilon = MathExtensions.Epsilon * 0.999f;
    boxMaximum += new Vector3D(AllowedValueEpsilon, AllowedValueEpsilon, AllowedValueEpsilon);
    var otherBox = new BoundingBox(Vector3D.Zero, boxMaximum);
    Assert.IsTrue(box.IsNearlyEqual(otherBox));
}

[Test]
public void CheckForNearlyEqual()
{
    var boxMaximum = Vector3D.One;
    var box = new BoundingBox(Vector3D.Zero, boxMaximum);
    const float AllowedValueEpsilon = MathExtensions.Epsilon * 0.999f;
    boxMaximum += new Vector3D(AllowedValueEpsilon, AllowedValueEpsilon, AllowedValueEpsilon);
    var otherBox = new BoundingBox(Vector3D.Zero, boxMaximum);
    Assert.IsTrue(box.IsNearlyEqual(otherBox));
}

[Test]
public void IntersectBoundingBoxWithBoundingBox()
{
    var box1 = new BoundingBox(Vector3D.Zero, Vector3D.One);
    var box2 = new BoundingBox(Vector3D.One / 2, Vector3D.One);
    Assert.IsTrue(box1.IsColliding(box2));
    var box3 = new BoundingBox(Vector3D.One * 2, Vector3D.One);
    Assert.IsFalse(box1.IsColliding(box3));
}

[Test]
public void IntersectBoundingBoxWithBoundingBox()
{
    var box1 = new BoundingBox(Vector3D.Zero, Vector3D.One);
    var box2 = new BoundingBox(Vector3D.One / 2, Vector3D.One);
    Assert.IsTrue(box1.IsColliding(box2));
    var box3 = new BoundingBox(Vector3D.One * 2, Vector3D.One);
    Assert.IsFalse(box1.IsColliding(box3));
}

[Test]
public void IntersectBoundingBoxWithBoundingSphere()
{
    var boundingBox = new BoundingBox(Vector3D.Zero, Vector3D.One);
    var sphere = new BoundingSphere(Vector3D.Zero, 0.5f);
    Assert.IsTrue(boundingBox.IsColliding(sphere));
}

[Test]
public void IntersectBoundingBoxWithBoundingSphere()
{
    var boundingBox = new BoundingBox(Vector3D.Zero, Vector3D.One);
    var sphere = new BoundingSphere(Vector3D.Zero, 0.5f);
    Assert.IsTrue(boundingBox.IsColliding(sphere));
}

[Test]
public void IntersectBoundingBoxWithRay()
{
    var boundingBox = new BoundingBox(Vector3D.One * -0.5f, Vector3D.One * 0.5f);
    var ray = new Ray(Vector3D.UnitY * 2.0f, -Vector3D.UnitY);
    Assert.AreEqual(new Vector3D(0.0f, 0.5f, 0.0f), boundingBox.Intersect(ray));
}

[Test]
public void IntersectBoundingBoxWithRay()
{
    var boundingBox = new BoundingBox(Vector3D.One * -0.5f, Vector3D.One * 0.5f);
    var ray = new Ray(Vector3D.UnitY * 2.0f, -Vector3D.UnitY);
    Assert.AreEqual(new Vector3D(0.0f, 0.5f, 0.0f), boundingBox.Intersect(ray));
}

[Test]
public void MissBoundingBoxWithRay()
{
    var boundingBox = new BoundingBox(Vector3D.One * -0.5f, Vector3D.One * 0.5f);
    var ray = new Ray(Vector3D.UnitZ * 2.0f, -Vector3D.UnitY);
    Assert.IsNull(boundingBox.Intersect(ray));
}

[Test]
public void MissBoundingBoxWithRay()
{
    var boundingBox = new BoundingBox(Vector3D.One * -0.5f, Vector3D.One * 0.5f);
    var ray = new Ray(Vector3D.UnitZ * 2.0f, -Vector3D.UnitY);
    Assert.IsNull(boundingBox.Intersect(ray));
}

[Test]
public void MissBoundingBoxWithRayFromBehind()
{
    var boundingBox = new BoundingBox(Vector3D.One * -0.5f, Vector3D.One * 0.5f);
    var ray = new Ray(Vector3D.UnitY * 2.0f, Vector3D.UnitY);
    Assert.IsNull(boundingBox.Intersect(ray));
}

[Test]
public void MissBoundingBoxWithRayFromBehind()
{
    var boundingBox = new BoundingBox(Vector3D.One * -0.5f, Vector3D.One * 0.5f);
    var ray = new Ray(Vector3D.UnitY * 2.0f, Vector3D.UnitY);
    Assert.IsNull(boundingBox.Intersect(ray));
}

[Test]
public void MergeTwoBoundingBoxes()
{
    var boxA = new BoundingBox(Vector3D.Zero, Vector3D.Zero);
    boxA.Merge(new BoundingBox(-Vector3D.One, Vector3D.One));
    Assert.AreEqual(boxA, new BoundingBox(-Vector3D.One, Vector3D.One));
    boxA.Merge(new BoundingBox(Vector3D.Zero, Vector3D.Zero));
    Assert.AreEqual(boxA, new BoundingBox(-Vector3D.One, Vector3D.One));
}

[Test]
public void MergeTwoBoundingBoxes()
{
    var boxA = new BoundingBox(Vector3D.Zero, Vector3D.Zero);
    boxA.Merge(new BoundingBox(-Vector3D.One, Vector3D.One));
    Assert.AreEqual(boxA, new BoundingBox(-Vector3D.One, Vector3D.One));
    boxA.Merge(new BoundingBox(Vector3D.Zero, Vector3D.Zero));
    Assert.AreEqual(boxA, new BoundingBox(-Vector3D.One, Vector3D.One));
}