public void LineAlgorithmsIsCollinearTest()
{
// collinear lines
Coordinate firstLineStart = new Coordinate(1, 1);
Coordinate firstLineEnd = new Coordinate(4, 1);
Coordinate secondLineStart = new Coordinate(1, 1);
Coordinate secondLineEnd = new Coordinate(4, 1);
Assert.IsTrue(LineAlgorithms.IsCollinear(firstLineStart, firstLineEnd, secondLineStart, secondLineEnd));
firstLineStart = new Coordinate(1, 1);
firstLineEnd = new Coordinate(4, 1);
secondLineStart = new Coordinate(1, 1);
secondLineEnd = new Coordinate(15, 1);
Assert.IsTrue(LineAlgorithms.IsCollinear(firstLineStart, firstLineEnd, secondLineStart, secondLineEnd));
firstLineStart = new Coordinate(1, 1);
firstLineEnd = new Coordinate(16, 1);
secondLineStart = new Coordinate(15, 1);
secondLineEnd = new Coordinate(2, 1);
Assert.IsTrue(LineAlgorithms.IsCollinear(firstLineStart, firstLineEnd, secondLineStart, secondLineEnd));
firstLineStart = new Coordinate(1, 1);
firstLineEnd = new Coordinate(4, 1);
secondLineStart = new Coordinate(15, 1);
secondLineEnd = new Coordinate(1, 1);
Assert.IsTrue(LineAlgorithms.IsCollinear(firstLineStart, firstLineEnd, secondLineStart, secondLineEnd));
firstLineStart = new Coordinate(1, 1);
firstLineEnd = new Coordinate(4, 1);
secondLineStart = new Coordinate(4, 1);
secondLineEnd = new Coordinate(-5, 1);
Assert.IsTrue(LineAlgorithms.IsCollinear(firstLineStart, firstLineEnd, secondLineStart, secondLineEnd));
firstLineStart = new Coordinate(20, 1);
firstLineEnd = new Coordinate(250, 1);
secondLineEnd = new Coordinate(1000, 1);
secondLineStart = new Coordinate(250, 1);
Assert.IsTrue(LineAlgorithms.IsCollinear(firstLineStart, firstLineEnd, secondLineStart, secondLineEnd));
firstLineStart = new Coordinate(20, 1);
firstLineEnd = new Coordinate(250, 1);
secondLineStart = new Coordinate(259, 1);
secondLineEnd = new Coordinate(1000, 1);
Assert.IsTrue(LineAlgorithms.IsCollinear(firstLineStart, firstLineEnd, secondLineStart, secondLineEnd));
// not collinear lines
firstLineStart = new Coordinate(20, 1);
firstLineEnd = new Coordinate(250, 1);
secondLineStart = new Coordinate(1, 100);
secondLineEnd = new Coordinate(1, 1200);
Assert.IsFalse(LineAlgorithms.IsCollinear(firstLineStart, firstLineEnd, secondLineStart, secondLineEnd));
firstLineStart = new Coordinate(20, 1);
firstLineEnd = new Coordinate(250, 1);
secondLineStart = new Coordinate(250, 1);
secondLineEnd = new Coordinate(1000, 2);
Assert.IsFalse(LineAlgorithms.IsCollinear(firstLineStart, firstLineEnd, secondLineStart, secondLineEnd));
firstLineStart = new Coordinate(1.2, 1.2);
firstLineEnd = new Coordinate(1.2, 7.2);
secondLineStart = new Coordinate(2.2, 8.2);
secondLineEnd = new Coordinate(2.2, 15.2);
Assert.IsFalse(LineAlgorithms.IsCollinear(firstLineStart, firstLineEnd, secondLineStart, secondLineEnd));
}