/**
 * The test class QuadraticEqnTest.
 *
 * @author  Phill Conrad
 * @version 05/07/2009 for CS10, lab04, UCSB
 */

public class QuadraticEqnTest extends junit.framework.TestCase
{

    /** declare a tolerance for testing doubles for equality
     */
    
    public static final double TOL = 0.00001; 

    /** test whether the getters for a, b, c work 
     */
        
    public void testConstructorAndGetters()
    {
        QuadraticEqn q = new QuadraticEqn(2.0, 3.0, 4.0);
        assertEquals(2.0, q.getA());
        assertEquals(3.0, q.getB());
        assertEquals(4.0, q.getC());
    }

    public void testNumRealRoots()
    {
        QuadraticEqn q = new QuadraticEqn(1.0, 5.0, -14.0);
        assertEquals( 2, q.numRealRoots());
        QuadraticEqn q2 = new QuadraticEqn(1.0, 6.0, 9.0);
        assertEquals( 1, q2.numRealRoots());
        QuadraticEqn q3 = new QuadraticEqn(1.0, 5.0, 13.0);
        assertEquals( 0, q3.numRealRoots());
    }
    
    public void testCalcDiscriminant()
    {
        QuadraticEqn q = new QuadraticEqn(1.0, 5.0, -14.0);
        assertEquals( (25-(4*(-14))), q.calcDiscriminant(), TOL);
    }
    
    public void testCalcDiscriminant1()
    {
        QuadraticEqn q2 = new QuadraticEqn(1.0, 6.0, 9.0);
        assertEquals( (36.0-(4.0*9.0)), q2.calcDiscriminant(), TOL);
    }
    
    public void testCalcDiscriminant2()
    {
        QuadraticEqn q3 = new QuadraticEqn(1.0, 5.0, 13.0);
        assertEquals( (25.0-(4.0*13.0)), q3.calcDiscriminant(), TOL);
    }
    
    public void testEvaluateForDouble1()
    {
        // if we evaluate ax^2 + bx + c for x=2, a=3, b=5, c=7
        //   we should get 3*2*2 + 5*2 + 7 =  12 + 10 + 7 = 29
        
        QuadraticEqn q = new QuadraticEqn(3.0, 5.0 ,7.0);
        assertEquals( 29.0, q.evaluate(2.0), TOL);
    }
    
    public void testEvaluateForDouble2()
    {
      // @@@ ADD ANOTHER UNIT TEST HERE---one of your own choosing
       //   that tests the evaluate function for doubles.  (See the one above)
       fail("You haven't written the body of the testEvaluateForDouble2 function yet!"); // @@@ Remove this line when done
    }

    public void testEvaluateForComplex1()
    {
        // Try the same test, using only the real parts of the complex number
        // if we evaluate ax^2 + bx + c for x=2, a=3, b=5, c=7
        //   we should get 3*2*2 + 5*2 + 7 =  12 + 10 + 7 = 29

        QuadraticEqn q = new QuadraticEqn(3.0, 5.0 ,7.0);
        Complex two = new Complex(2.0, 0.0);
       
        assertTrue( new Complex(29.0, 0.0).approxEquals(q.evaluate(two),TOL));
    }

    public void testEvaluateForComplex2()
    {
        // if we evaluate ax^2 + bx + c for x=2 + 3i, a=5, b=7, c=11
        //   we should get:
        //           5 * (2 + 3i) * (2 * 3i)   = 5 * (4 + 12i - 9) = 5 ( -5 + 12i) = -25 + 60i
        //     plus  7 * (2 + 3i)                                                  =  14 + 21i
        //     plus  11                                                            =  11
        // Grand total: 0.0 + 81i

        QuadraticEqn q = new QuadraticEqn(5.0, 7.0 ,11.0);
        Complex c = new Complex(2.0, 3.0);
       
        assertTrue( new Complex(0.0, 81.0).approxEquals(q.evaluate(c),TOL));
    }
    
    public void testEvaluateForComplex3()
    {
      // @@@ ADD ANOTHER UNIT TEST HERE---one of your own choosing
       //   that tests the evaluate function for Complex numbers.  (See the one above)
       fail("You haven't written the body of the testEvaluateForComplex3 function yet!"); // @@@ Remove this line when done
    }
    
    public void ultimateRealRootTestRealVersion()
    {
        // the ultimate test: calculate the real roots of a quadratic equation,
        // the evaluate the equation at those roots, and see if they give us zero
        
        // We'll use (2x + 3)(5x - 7), which gives us 10x^2 + x -21
        // The real roots should be 2x + 3 = 0    and  5x - 7 = 0
        //   which should be x = -3/2 = -1.5  and 7/5 = 1.4
        // To figure out which root is which, we'll need to apply the quadratic formula:
        //   ( -1 + sqrt(1 - 4(10)(-21) ) / 20   gives us: (-1 + 29 ) / 20  = 1.4
        // So 1.4 should be root1, and -1.5 should be root2
        
        QuadraticEqn q = new QuadraticEqn(10, 1, -21);
        
        assertEquals(2, q.numRealRoots());
        assertEquals(1.4, q.realRoot1(), TOL);
        assertEquals(-1.5, q.realRoot2(), TOL);
      
        // and the ultimate test... does it evaluate to zero at its two roots?
        
        assertEquals(0.0, q.evaluate(q.realRoot1()), TOL);
        assertEquals(0.0, q.evaluate(q.realRoot2()), TOL);
        
    }

    public void ultimateRealRootTestComplexVersion1()
    {
        // the ultimate test: calculate the real roots of a quadratic equation,
        // the evaluate the equation at those roots, and see if they give us zero
        
        // We'll use (2x + 3)(5x - 7), which gives us 10x^2 + x -21
        // The real roots should be 2x + 3 = 0    and  5x - 7 = 0
        //   which should be x = -3/2 = -1.5  and 7/5 = 1.4
        // To figure out which root is which, we'll need to apply the quadratic formula:
        //   ( -1 + sqrt(1 - 4(10)(-21) ) / 20   gives us: (-1 + 29 ) / 20  = 1.4
        // So 1.4 should be root1, and -1.5 should be root2
        
        QuadraticEqn q = new QuadraticEqn(10, 1, -21);
        
        assertEquals(2, q.numRealRoots());
        assertTrue(new Complex(1.4,0.0).approxEquals(q.complexRoot1(), TOL));
        assertTrue(new Complex(-1.5,0.0).approxEquals(q.complexRoot2(), TOL));

         // and the ultimate test... does it evaluate to zero at its two roots?
        
        Complex zero = new Complex();
        assertTrue(zero.approxEquals(q.complexRoot1(), TOL));
        assertTrue(zero.approxEquals(q.complexRoot2(), TOL));
         
    }

}