### Question:
CSSColorHelper { @Nonnull @Nonempty public static String getHexColorValue (final int nRed, final int nGreen, final int nBlue) { return new StringBuilder (CCSSValue.HEXVALUE_LENGTH).append (CCSSValue.PREFIX_HEX) .append (_getRGBPartAsHexString (nRed)) .append (_getRGBPartAsHexString (nGreen)) .append (_getRGBPartAsHexString (nBlue)) .toString (); } private  CSSColorHelper(); static boolean isColorValue(@Nullable final String sValue); static boolean isRGBColorValue(@Nullable final String sValue); @Nullable static CSSRGB getParsedRGBColorValue(@Nullable final String sValue); static boolean isRGBAColorValue(@Nullable final String sValue); @Nullable static CSSRGBA getParsedRGBAColorValue(@Nullable final String sValue); static boolean isHSLColorValue(@Nullable final String sValue); @Nullable static CSSHSL getParsedHSLColorValue(@Nullable final String sValue); static boolean isHSLAColorValue(@Nullable final String sValue); @Nullable static CSSHSLA getParsedHSLAColorValue(@Nullable final String sValue); static boolean isHexColorValue(@Nullable final String sValue); @Nonnegative static int getRGBValue(final int nRGBPart); @Nonnegative static float getOpacityToUse(final float fOpacity); @Nonnull @Nonempty static String getRGBColorValue(final int nRed, final int nGreen, final int nBlue); @Nonnull @Nonempty static String getRGBAColorValue(final int nRed, final int nGreen, final int nBlue, final float fOpacity); @Nonnegative static int getHSLHueValue(final int nHSLPart); @Nonnegative static float getHSLHueValue(final float fHSLPart); @Nonnegative static int getHSLPercentageValue(final int nHSLPart); @Nonnegative static float getHSLPercentageValue(final float nHSLPart); @Nonnull @Nonempty static String getHSLColorValue(final int nHue, final int nSaturation, final int nLightness); @Nonnull @Nonempty static String getHSLColorValue(final float fHue, final float fSaturation, final float fLightness); @Nonnull @Nonempty static String getHSLAColorValue(final int nHue, final int nSaturation, final int nLightness, final float fOpacity); @Nonnull @Nonempty static String getHSLAColorValue(final float fHue, final float fSaturation, final float fLightness, final float fOpacity); @Nonnull @Nonempty static String getHexColorValue(final int nRed, final int nGreen, final int nBlue); @Nonnull @Nonempty static float [] getRGBAsHSLValue(final int nRed, final int nGreen, final int nBlue); @Nonnull @Nonempty static int [] getHSLAsRGBValue(final float fHue, final float fSaturation, final float fLightness); static final int RGB_MIN; static final int RGB_MAX; static final int RGB_RANGE; static final int HSL_MIN; static final int HSL_MAX; static final int HSL_RANGE; static final int PERCENTAGE_MIN; static final int PERCENTAGE_MAX; static final float OPACITY_MIN; static final float OPACITY_MAX; }### Answer:
@Test @SuppressFBWarnings ("TQ_NEVER_VALUE_USED_WHERE_ALWAYS_REQUIRED") public void testColorHex () { assertEquals ("#000000", CSSColorHelper.getHexColorValue (0, 0, 0)); assertEquals ("#0f80ff", CSSColorHelper.getHexColorValue (15, 128, 255)); assertEquals ("#000000", CSSColorHelper.getHexColorValue (256, 256, 256)); assertEquals ("#010101", CSSColorHelper.getHexColorValue (257, 257, 257)); assertEquals ("#ffffff", CSSColorHelper.getHexColorValue (-1, -1, -1)); }