public void FindRoots_RealRootsAllIdentical_ReturnsCorrectAnswer()
{
double a = 1;
double b = -3;
double c = 3;
double d = -1;
List <Complex> roots = CubicSolver.FindRoots(a, b, c, d);
Complex root = new Complex(1, 0);
Assert.AreEqual(3, roots.Count);
Assert.AreEqual(3, roots.Count(x => x == root));
}
public void FindRoots_RealRootsTwoIdentical_ReturnsCorrectAnswer()
{
double a = 1;
double b = -5;
double c = 8;
double d = -4;
List <Complex> roots = CubicSolver.FindRoots(a, b, c, d);
Complex root1 = new Complex(1, 0);
Complex root2 = new Complex(2, 0);
Assert.AreEqual(3, roots.Count);
Assert.IsTrue(roots.Exists(x => x == root1));
Assert.AreEqual(2, roots.Count(x => x == root2));
}
public void FindRoots_QuadraticEquation_ReturnsCorrectAnswer()
{
double a = 0;
double b = 1;
double c = -4;
double d = 4;
List <Complex> roots = CubicSolver.FindRoots(a, b, c, d);
Complex root1 = new Complex(2, 0);
Complex root2 = new Complex(2, 0);
Assert.AreEqual(2, roots.Count);
Assert.IsTrue(roots.Exists(x => x == root1));
Assert.IsTrue(roots.Exists(x => x == root2));
}
public void FindRoots_TwoComplexRoots_ReturnsCorrectAnswer()
{
double a = 1;
double b = 3;
double c = 1;
double d = 3;
List <Complex> roots = CubicSolver.FindRoots(a, b, c, d);
Complex root1 = new Complex(-3, 0);
Complex root2 = new Complex(0, 1);
Complex root3 = new Complex(0, -1);
Assert.AreEqual(3, roots.Count);
Assert.IsTrue(roots.Exists(x => x == root1));
Assert.IsTrue(roots.Exists(x => x == root2));
Assert.IsTrue(roots.Exists(x => x == root3));
}
public void FindRoots_ThreeDistinctRealRoots_ReturnsCorrectAnswer()
{
double a = 1;
double b = -6;
double c = 11;
double d = -6;
List <Complex> roots = CubicSolver.FindRoots(a, b, c, d);
Complex root1 = new Complex(1, 0);
Complex root2 = new Complex(2, 0);
Complex root3 = new Complex(3, 0);
Assert.AreEqual(3, roots.Count);
Assert.IsTrue(roots.Exists(x => x == root1));
Assert.IsTrue(roots.Exists(x => x == root2));
Assert.IsTrue(roots.Exists(x => x == root3));
}