Enhance color tests to capture correct behaviour of \setbox and \box with respect to color and background color adjustment

Author: brucemiller

t/graphics/xcolors.pdf

@@ -246,12 +246,19 @@ \section{Color Compararisons}
 \end{testcolors}
 \endgroup
 
-\section{Boxes}
+\section{Setting and Using Boxes}
 \newbox\mybox
-\setbox\mybox=\hbox{Should NOT be Red!}
+{\color{red}\global\setbox\mybox=\hbox{Black on White!}}
+\copy\mybox
+
+\setbox\mybox=\hbox{{\color{black}\colorbox{white}{Black on White!}}}
 \copy\mybox
-\setbox\mybox=\hbox{Should be Red!}
-{\color{red}\copy\mybox}
+
+\setbox\mybox=\hbox{Red on Green!}
+{\color{red}\colorbox{green}{\copy\mybox}}
+
+\setbox\mybox=\hbox{Red on Green, but \color{green}\colorbox{blue}{Green on Blue!}}
+{\color{red}\colorbox{green}{\copy\mybox}}
 
 \section{Custom rgb directives}
 \color{rgb:red,4;green,2;yellow,1} Brown

t/graphics/xcolors.tex

@@ -642,10 +642,18 @@ A=100*13 = 1300pt;</p>
       <tag role="refnum">11</tag>
       <tag role="typerefnum">§11</tag>
     </tags>
-    <title><tag close=" ">11</tag>Boxes</title>
+    <title><tag close=" ">11</tag>Setting and Using Boxes</title>
     <para xml:id="S11.p1">
-      <p>Should NOT be Red!
-<text color="#FF0000">Should be Red!</text></p>
+      <p>Black on White!</p>
+    </para>
+    <para xml:id="S11.p2">
+      <p><text backgroundcolor="#FFFFFF" color="#000000">Black on White!</text></p>
+    </para>
+    <para xml:id="S11.p3">
+      <p><text backgroundcolor="#00FF00" color="#FF0000">Red on Green!</text></p>
+    </para>
+    <para xml:id="S11.p4">
+      <p><text backgroundcolor="#00FF00" color="#FF0000">Red on Green, but <text backgroundcolor="#0000FF" color="#00FF00">Green on Blue!</text></text></p>
     </para>
   </section>
   <section inlist="toc" xml:id="S12">