gistfile1.java

import org.junit.Before;
import org.junit.Test;

import static org.junit.Assert.assertNotEquals;
import static org.junit.Assert.assertTrue;

/**
 * @author Murzinov Ilya, murz42@gmail.com
 *         Date 12.06.14
 */
public class RtriangleProviderTests {
    /**
     * Let sideA be length of the side between (X1, Y1) and (X2, Y2).
     * Let sideB be length of the side between (X2, Y2) and (X3, Y3).
     * Let sideC be length of the side between (X1, Y1) and (X3, Y3).
     */
    private Rtriangle rtriangle = RtriangleProvider.getRtriangle();
    private double sideA;
    private double sideB;
    private double sideC;

    @Before
    public void init() {
        sideA = Math.sqrt(Math.pow(rtriangle.getApexX1() - rtriangle.getApexX2(), 2)
                + Math.pow(rtriangle.getApexY1() - rtriangle.getApexY2(), 2));
        sideB = Math.sqrt(Math.pow(rtriangle.getApexX2() - rtriangle.getApexX3(), 2)
                + Math.pow(rtriangle.getApexY2() - rtriangle.getApexY3(), 2));
        sideC = Math.sqrt(Math.pow(rtriangle.getApexX1() - rtriangle.getApexX3(), 2)
                + Math.pow(rtriangle.getApexY1() - rtriangle.getApexY3(), 2));
    }

    @Test
    public void sideAShouldNotBeZeroTest() {
        assertNotEquals(0d, sideA);
    }

    @Test
    public void sideBShouldNotBeZeroTest() {
        assertNotEquals(0d, sideB);
    }

    @Test
    public void sideCShouldNotBeZeroTest() {
        assertNotEquals(0d, sideC);
    }

    @Test
    public void triangleInequalityShouldHold() {
        assertTrue("Triangle inequality should hold", sideA + sideB > sideC
                || sideA + sideC > sideB
                || sideC + sideB > sideA);
    }

    @Test
    public void pythagoreanTheoremShouldHold() {
        assertTrue("Pythagorean theorem should hold",
                Math.pow(sideA, 2) + Math.pow(sideB, 2) == Math.pow(sideC, 2)
                || Math.pow(sideA, 2) + Math.pow(sideC, 2) == Math.pow(sideB, 2)
                || Math.pow(sideB, 2) + Math.pow(sideC, 2) == Math.pow(sideA, 2));
    }
}

interface Rtriangle {
    int getApexX1();
    int getApexY1();
    int getApexX2();
    int getApexY2();
    int getApexX3();
    int getApexY3();
}

/**
 * RtriangleProvider stub.
 */
final class RtriangleProvider {
    public static Rtriangle getRtriangle() {
        return new Rtriangle() {
            @Override
            public int getApexX1() {
                return 0;
            }

            @Override
            public int getApexY1() {
                return 0;
            }

            @Override
            public int getApexX2() {
                return 0;
            }

            @Override
            public int getApexY2() {
                return 0;
            }

            @Override
            public int getApexX3() {
                return 0;
            }

            @Override
            public int getApexY3() {
                return 0;
            }
        };
    }
}