Testtriangle.java

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import org.junit.Before;  
import org.junit.Test;  
  
import java.util.Arrays;

public class Testtriangle {  
    Rtriangle triangle;

    @Before  
    public void setUp() {  
        triangle = RtriangleProvider.getRtriangle();  
    }  
  
    @Test  
    public void test() {
        int x1 = triangle.getApexX1();   
        int y1 = triangle.getApexY1();   
        int x2 = triangle.getApexX2();   
        int y2 = triangle.getApexY2();   
        int x3 = triangle.getApexX3();   
        int y3 = triangle.getApexY3();

        double[] lengths = {
            distQuad(x1, y1, x2, y2),
            distQuad(x2, y2, x3, y3),
            distQuad(x1, y1, x3, y3)
        };

        Arrays.sort(lengths);

        assertEquals(lengths[0] + lengths[1], lengths[2], 0); 
        assertTrue(oneLine(x1, y1, x2, y2, x3, y3) != 0);
    }

    private double distQuad(int x1, int y1, int x2, int y2){
        return (x1 - x2)*(x1 - x2) + (y1 - y2)*(y1 - y2);
    }

    private double oneLine(int x1, int y1, int x2, int y2, int x3, int y3){
        return (x1 - x3)*(y2 - y3) - (x2 - x3)*(y1 - y3);
    }
}