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

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

import com.montecarlo.geometry.Arc;
import com.montecarlo.geometry.FigureDebf;
import com.montecarlo.geometry.Point;
import com.montecarlo.geometry.Triangle;
import org.junit.Before;
import org.junit.Test;

import static org.junit.Assert.*;

/**
 * Unit tests for {@link FigureDebf} — the composite figure "debf".
 *
 * <h3>Default geometry</h3>
 * <pre>
 *   Rectangle ABCD = [0,4]×[0,4]
 *   B=(4,0)  E=(4,2)  F=(2,0)  D=(0,4)
 *
 *   Triangle BEF : area = 2
 *   Semicircle   : centre=(3,1), r=√2, D-side, area = π
 *   Total        : 2 + π ≈ 5.14159265…
 *
 *   The two components are on opposite sides of chord FE (line y = x − 2):
 *     Triangle BEF is on the B-side (x − y ≥ 2)
 *     Semicircle   is on the D-side (x − y ≤ 2)
 *   → zero overlap → areas add directly.
 * </pre>
 */
public class FigureDebfTest {

    private FigureDebf figure;

    @Before
    public void setUp() {
        Triangle triangle = new Triangle(
            new Point(4, 0),   // B
            new Point(4, 2),   // E
            new Point(2, 0)    // F
        );
        Arc arc = new Arc(
            new Point(3, 1),           // centre = midpoint(F, E)
            Math.sqrt(2),              // radius = |FE| / 2
            new Point(0, 4)            // D — reference towards D-side
        );
        figure = new FigureDebf(triangle, arc);
    }

    // -----------------------------------------------------------------------
    // Analytical area
    // -----------------------------------------------------------------------

    @Test
    public void testAnalyticalArea() {
        assertEquals(2 + Math.PI, figure.analyticalArea(), 1e-12);
    }

    @Test
    public void testTriangleArea() {
        assertEquals(2.0, figure.getTriangle().analyticalArea(), 1e-12);
    }

    @Test
    public void testSemicircleArea() {
        assertEquals(Math.PI, figure.getArc().analyticalArea(), 1e-12);
    }

    // -----------------------------------------------------------------------
    // contains — triangle interior
    // -----------------------------------------------------------------------

    @Test
    public void testContainsCentroidBEF() {
        // Centroid of BEF: (10/3, 2/3) — inside the triangle
        assertTrue(figure.contains(new Point(10.0 / 3, 2.0 / 3)));
    }

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

    // -----------------------------------------------------------------------
    // contains — semicircle interior
    // -----------------------------------------------------------------------

    @Test
    public void testContainsSemicircleInterior() {
        // (2.5, 1.5): inside the semicircle
        assertTrue(figure.contains(new Point(2.5, 1.5)));
    }

    @Test
    public void testContainsSemicircleLeftExtreme() {
        // (3−√2, 1): leftmost point of the semicircle
        assertTrue(figure.contains(new Point(3 - Math.sqrt(2), 1)));
    }

    // -----------------------------------------------------------------------
    // contains — shared boundary (chord FE)
    // -----------------------------------------------------------------------

    @Test
    public void testContainsMidpointOfChordFE() {
        // (3, 1) is the centre of the arc AND midpoint of hypotenuse EF → boundary of both
        assertTrue(figure.contains(new Point(3, 1)));
    }

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

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

    @Test
    public void testNotContainsTopLeft() {
        assertFalse(figure.contains(new Point(0, 4)));  // D is a reference, not inside the figure
    }

    @Test
    public void testNotContainsFarPoint() {
        assertFalse(figure.contains(new Point(10, 10)));
    }

    @Test
    public void testNotContainsAboveTriangleAndOutsideSemicircle() {
        // (1, 3): not in triangle (too far left/up) and not in semicircle (dist > √2 from (3,1))
        assertFalse(figure.contains(new Point(1, 3)));
    }

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

    @Test
    public void testBoundingBoxMinX() {
        // min(triangle.minX, arc.minX) = min(2, 3−√2) = 3−√2 ≈ 1.586
        double expected = 3 - Math.sqrt(2);
        assertEquals(expected, figure.getBoundingBox().getMinX(), 1e-10);
    }

    @Test
    public void testBoundingBoxMinY() {
        assertEquals(0.0, figure.getBoundingBox().getMinY(), 1e-10);
    }

    @Test
    public void testBoundingBoxMaxX() {
        assertEquals(4.0, figure.getBoundingBox().getMaxX(), 1e-10);
    }

    @Test
    public void testBoundingBoxMaxY() {
        // max(triangle.maxY, arc.maxY) = max(2, 1+√2) = 1+√2 ≈ 2.414
        double expected = 1 + Math.sqrt(2);
        assertEquals(expected, figure.getBoundingBox().getMaxY(), 1e-10);
    }
}