src/test/java/com/montecarlo/tests/TriangleTest.java - master - shvidkuli/kkrjava

src/test/java/com/montecarlo/tests/TriangleTest.java
147 строк4 KB
kroc400
first_commit
30 апр 2026, 22:44
30 апр 2026, 22:442347fdb
package com.montecarlo.tests;

import com.montecarlo.geometry.BoundingBox;
import com.montecarlo.geometry.Point;
import com.montecarlo.geometry.Triangle;
import org.junit.Test;

import static org.junit.Assert.*;

/**
 * Unit tests for {@link Triangle}.
 *
 * <p>Uses the default triangle BEF from the figure "debf":
 * <pre>
 *   B = (4, 0)   E = (4, 2)   F = (2, 0)
 *   Area = 2
 * </pre>
 * </p>
 */
public class TriangleTest {

    // Triangle BEF: b=(4,0), e=(4,2), f=(2,0)
    private static final Triangle BEF = new Triangle(
        new Point(4, 0),
        new Point(4, 2),
        new Point(2, 0)
    );

    // -----------------------------------------------------------------------
    // Area
    // -----------------------------------------------------------------------

    @Test
    public void testAreaDefault() {
        assertEquals("Area of BEF must be 2.0", 2.0, BEF.analyticalArea(), 1e-12);
    }

    @Test
    public void testAreaUnitRightTriangle() {
        Triangle t = new Triangle(new Point(0, 0), new Point(1, 0), new Point(0, 1));
        assertEquals(0.5, t.analyticalArea(), 1e-12);
    }

    @Test
    public void testAreaEquilateral() {
        // Equilateral triangle with side 2: area = √3
        Triangle t = new Triangle(
            new Point(0, 0), new Point(2, 0), new Point(1, Math.sqrt(3))
        );
        assertEquals(Math.sqrt(3), t.analyticalArea(), 1e-10);
    }

    // -----------------------------------------------------------------------
    // contains — vertices (on boundary → must return true)
    // -----------------------------------------------------------------------

    @Test
    public void testContainsVertexB() {
        assertTrue(BEF.contains(new Point(4, 0)));
    }

    @Test
    public void testContainsVertexE() {
        assertTrue(BEF.contains(new Point(4, 2)));
    }

    @Test
    public void testContainsVertexF() {
        assertTrue(BEF.contains(new Point(2, 0)));
    }

    // -----------------------------------------------------------------------
    // contains — edge midpoints (boundary)
    // -----------------------------------------------------------------------

    @Test
    public void testContainsMidpointBE() {
        // Midpoint of BE: (4, 1)
        assertTrue(BEF.contains(new Point(4, 1)));
    }

    @Test
    public void testContainsMidpointEF() {
        // Midpoint of EF: (3, 1)  — lies on the hypotenuse
        assertTrue(BEF.contains(new Point(3, 1)));
    }

    @Test
    public void testContainsMidpointBF() {
        // Midpoint of BF: (3, 0)
        assertTrue(BEF.contains(new Point(3, 0)));
    }

    // -----------------------------------------------------------------------
    // contains — centroid (strictly inside)
    // -----------------------------------------------------------------------

    @Test
    public void testContainsCentroid() {
        // Centroid = ((4+4+2)/3, (0+2+0)/3) = (10/3, 2/3)
        assertTrue(BEF.contains(new Point(10.0 / 3, 2.0 / 3)));
    }

    // -----------------------------------------------------------------------
    // contains — points strictly outside
    // -----------------------------------------------------------------------

    @Test
    public void testNotContainsOrigin() {
        assertFalse(BEF.contains(new Point(0, 0)));
    }

    @Test
    public void testNotContainsAboveHypotenuse() {
        // (2, 2): above the hypotenuse line y = x − 2
        assertFalse(BEF.contains(new Point(2, 2)));
    }

    @Test
    public void testNotContainsLeftOfFigure() {
        assertFalse(BEF.contains(new Point(1, 1)));
    }

    @Test
    public void testNotContainsAboveTriangle() {
        assertFalse(BEF.contains(new Point(3, 2)));
    }

    // -----------------------------------------------------------------------
    // Bounding box
    // -----------------------------------------------------------------------

    @Test
    public void testBoundingBox() {
        BoundingBox bb = BEF.getBoundingBox();
        assertEquals(2.0, bb.getMinX(), 1e-12);
        assertEquals(0.0, bb.getMinY(), 1e-12);
        assertEquals(4.0, bb.getMaxX(), 1e-12);
        assertEquals(2.0, bb.getMaxY(), 1e-12);
    }

    @Test
    public void testBoundingBoxArea() {
        // bounding box of BEF = [2,4]×[0,2] → area = 4
        assertEquals(4.0, BEF.getBoundingBox().area(), 1e-12);
    }
}