defineSuite([
        'Core/CubicRealPolynomial',
        'Core/Math'
    ], function(
        CubicRealPolynomial,
        CesiumMath) {
    'use strict';

    it('discriminant throws without a', function() {
        expect(function() {
            CubicRealPolynomial.computeDiscriminant();
        }).toThrowDeveloperError();
    });

    it('discriminant throws without b', function() {
        expect(function() {
            CubicRealPolynomial.computeDiscriminant(1.0);
        }).toThrowDeveloperError();
    });

    it('discriminant throws without c', function() {
        expect(function() {
            CubicRealPolynomial.computeDiscriminant(1.0, 1.0);
        }).toThrowDeveloperError();
    });

    it('discriminant throws without d', function() {
        expect(function() {
            CubicRealPolynomial.computeDiscriminant(1.0, 1.0, 1.0);
        }).toThrowDeveloperError();
    });

    it('discriminant', function() {
        var a = 3.0;
        var b = 2.0;
        var c = 1.0;
        var d = 1.0;
        var expected = b*b*c*c - 4*a*c*c*c - 4*b*b*b*d - 27*a*a*d*d + 18*a*b*c*d;
        var actual = CubicRealPolynomial.computeDiscriminant(a, b, c, d);
        expect(actual).toEqualEpsilon(expected, CesiumMath.EPSILON14);
    });

    it('real roots throws without a', function() {
        expect(function() {
            CubicRealPolynomial.computeRealRoots();
        }).toThrowDeveloperError();
    });

    it('real roots throws without b', function() {
        expect(function() {
            CubicRealPolynomial.computeRealRoots(1.0);
        }).toThrowDeveloperError();
    });

    it('real roots throws without c', function() {
        expect(function() {
            CubicRealPolynomial.computeRealRoots(1.0, 1.0);
        }).toThrowDeveloperError();
    });

    it('real roots throws without d', function() {
        expect(function() {
            CubicRealPolynomial.computeRealRoots(1.0, 1.0, 1.0);
        }).toThrowDeveloperError();
    });

    it('three repeated roots', function() {
        var roots = CubicRealPolynomial.computeRealRoots(2.0, -12.0, 24.0, -16.0);
        expect(roots.length).toEqual(3);
        expect(roots[0]).toEqualEpsilon(2.0, CesiumMath.EPSILON15);
        expect(roots[1]).toEqualEpsilon(2.0, CesiumMath.EPSILON15);
        expect(roots[2]).toEqualEpsilon(2.0, CesiumMath.EPSILON15);
    });

    it('one unique and two repeated roots', function() {
        var roots = CubicRealPolynomial.computeRealRoots(2.0, 2.0, -2.0, -2.0);
        expect(roots.length).toEqual(3);
        expect(roots[0]).toEqualEpsilon(-1.0, CesiumMath.EPSILON15);
        expect(roots[1]).toEqualEpsilon(-1.0, CesiumMath.EPSILON15);
        expect(roots[2]).toEqualEpsilon(1.0, CesiumMath.EPSILON15);
    });

    it('three unique roots', function() {
        var roots = CubicRealPolynomial.computeRealRoots(2.0, 6.0, -26.0, -30.0);
        expect(roots.length).toEqual(3);
        expect(roots[0]).toEqualEpsilon(-5.0, CesiumMath.EPSILON15);
        expect(roots[1]).toEqualEpsilon(-1.0, CesiumMath.EPSILON15);
        expect(roots[2]).toEqualEpsilon(3.0, CesiumMath.EPSILON15);
    });

    it('complex roots', function() {
        var roots = CubicRealPolynomial.computeRealRoots(2.0, -6.0, 10.0, -6.0);
        expect(roots.length).toEqual(1);
        expect(roots[0]).toEqualEpsilon(1.0, CesiumMath.EPSILON15);
    });

    it('quadratic case', function() {
        var roots = CubicRealPolynomial.computeRealRoots(0.0, 2.0, -4.0, -6.0);
        expect(roots.length).toEqual(2);
        expect(roots[0]).toEqual(-1.0);
        expect(roots[1]).toEqual(3.0);
    });

    it('deflated case', function() {
        var roots = CubicRealPolynomial.computeRealRoots(1.0, 0.0, 1.0, 2.0);
        expect(roots.length).toEqual(1);
        expect(roots[0]).toEqualEpsilon(-1.0, CesiumMath.EPSILON14);

        roots = CubicRealPolynomial.computeRealRoots(1.0, 0.0, 0.0, -8.0);
        expect(roots.length).toEqual(3);
        expect(roots[0]).toEqualEpsilon(2.0, CesiumMath.EPSILON14);

        roots = CubicRealPolynomial.computeRealRoots(1.0, 0.0, -1.0, 0.0);
        expect(roots.length).toEqual(3);
        expect(roots[0]).toEqual(-1.0);
        expect(roots[1]).toEqual(0.0);
        expect(roots[2]).toEqual(1.0);

        roots = CubicRealPolynomial.computeRealRoots(1.0, 1.0, 0.0, 0.0);
        expect(roots.length).toEqual(3);
        expect(roots[0]).toEqual(-1.0);
        expect(roots[1]).toEqual(0.0);
        expect(roots[2]).toEqual(0.0);

        roots = CubicRealPolynomial.computeRealRoots(1.0, -1.0, 0.0, 0.0);
        expect(roots.length).toEqual(3);
        expect(roots[0]).toEqual(0.0);
        expect(roots[1]).toEqual(0.0);
        expect(roots[2]).toEqual(1.0);

        roots = CubicRealPolynomial.computeRealRoots(1.0, 1.0, 1.0, 0.0);
        expect(roots.length).toEqual(1);
        expect(roots[0]).toEqual(0.0);
    });
});