アルファ値を持つ16進数文字列からColorオブジェクトを作成するテスト

AlphaDigitsHexNumberColorDecodingTest.java

import static org.junit.Assert.*;

import java.awt.Color;

import org.junit.Test;

public class AlphaDigitsHexNumberColorDecodingTest {
    @Test
    public void decodeHexStringToColor() {
        Color color = Color.decode("#000000");
        assertEquals("no-alpha", 255, color.getAlpha());
        assertEquals("red", 0, color.getRed());
        assertEquals("blue", 0, color.getBlue());
        assertEquals("green", 0, color.getGreen());
    }
    
    @Test
    public void decodeHexStringToColorWithAlpha() {
        assertEquals("decode method ignores alpha digits",
                255, Color.decode("#00000000").getAlpha());
        assertEquals("color construction with alpha",
                0, new Color(Integer.decode("#00000000").intValue(), true).getAlpha());
    }
    
    @Test
    public void overflowToDecodeHexString() {
        assertEquals("max value of integer",
                127, new Color(Integer.decode("#7FFFFFFF").intValue(), true).getAlpha());
        
        Integer result = null;
        try {
            result = Integer.decode("#80000000");
        }
        catch (NumberFormatException expected) {
            assertNull("cannot format #80000000", result);
            return;
        }
        fail("unreachable");
    }
    
    @Test
    public void decodeHexStringUsingDecodeOfLong() {
        Color decode = new Color(Long.decode("#FFFFFFFF").intValue(), true);
        assertEquals("alpha", 255, decode.getAlpha());
        assertEquals("red", 255, decode.getRed());
        assertEquals("blue", 255, decode.getBlue());
        assertEquals("green", 255, decode.getGreen());
    }
}