slopetest.java

来自「BOOK:Beginning Algorithms Code Example」· Java 代码 · 共 44 行

package com.wrox.algorithms.geometry;

import junit.framework.TestCase;

/**
 */
public class SlopeTest extends TestCase {
    public void testIsVertical() {
        assertTrue(new Slope(4, 0).isVertical());
        assertTrue(new Slope(0, 0).isVertical());
        assertTrue(new Slope(-5, 0).isVertical());
        assertFalse(new Slope(0, 5).isVertical());
        assertFalse(new Slope(0, -5).isVertical());
    }

    public void testEquals() {
        assertTrue(new Slope(0, -5).equals(new Slope(0, 10)));
        assertTrue(new Slope(1, 3).equals(new Slope(2, 6)));
        assertFalse(new Slope(1, 3).equals(new Slope(-1, 3)));
        assertFalse(new Slope(1, 3).equals(new Slope(1, -3)));
        assertTrue(new Slope(5, 0).equals(new Slope(9, 0)));
    }

    public void testAsDoubleForNonVerticalSlope() {
        assertEquals(0, new Slope(0, 4).asDouble(), 0);
        assertEquals(0, new Slope(0, -4).asDouble(), 0);
        assertEquals(1, new Slope(3, 3).asDouble(), 0);
        assertEquals(1, new Slope(-3, -3).asDouble(), 0);
        assertEquals(-1, new Slope(3, -3).asDouble(), 0);
        assertEquals(-1, new Slope(-3, 3).asDouble(), 0);
        assertEquals(2, new Slope(6, 3).asDouble(), 0);
        assertEquals(1.5, new Slope(6, 4).asDouble(), 0);
    }

    public void testAsDoubleFailsForVerticalSlope() {
        try {
            new Slope(4, 0).asDouble();
            fail("should have blown up!");
        } catch (IllegalStateException e) {
            assertEquals("Vertical slope cannot be represented as double", e.getMessage());
        }
    }
}