\documentclass{article}
\begin{document}
\def\foo{FOO}
\catcode`*=\active
\def*{STAR}

\section{Basic noexpand}
X: X\relax\par
noexpand X: \noexpand X \relax\par
foo:\foo\relax\par
noexpand foo: \noexpand\foo\relax\par
*:*\relax\par
noexpand *: \noexpand*\relax\par
square: ${}^2\relax$\par
noexpand square: ${}\noexpand^2\relax$\par

\section{Basic unexpanded}
X: X\relax\par
unexpanded X: \unexpanded{X} \relax\par
foo:\foo\relax\par
unexpanded foo: \unexpanded{\foo}\relax\par
*:*\relax\par
unexpanded *: \unexpanded{*}\relax\par
square: ${}^2\relax$\par
unexpanded square: ${}\unexpanded{^2}\relax$\par


\section{Noexpand in defs}
\def\nfoo{\noexpand\foo}
\edef\enfoo{\noexpand\foo}
\expandafter\def\expandafter\eafoo\expandafter{\noexpand\foo}
\let\letfoo\foo
\expandafter\let\expandafter\letnxfoo\noexpand\foo

def noexpand foo: \nfoo\relax\par
edef noexpand foo: \enfoo\relax\par
expandafter def noexpand foo: \eafoo\relax\par
letfoo: \letfoo\relax\par
letnxfoo: \letnxfoo\relax\par
{[Change foo]
\def\foo{foo?}
edef noexpand foo: \enfoo\relax\par
expandafter def noexpand foo: \eafoo\relax\par
}
\section{Unexpanded in defs}
\def\nfoo{\unexpanded{\foo}}
\edef\enfoo{\unexpanded{\foo}}
\expandafter\def\expandafter\eafoo\expandafter{\unexpanded{\foo}}

def unexpanded foo: \nfoo\relax\par
edef unexpanded foo: \enfoo\relax\par
expandafter def unexpanded foo: \eafoo\relax\par
{[Change foo]
\def\foo{foo?}
edef unexpanded foo: \enfoo\relax\par
expandafter def unexpanded foo: \eafoo\relax\par
}

\section{Random}

\def\now#1{NOW #1}

\def\later#1{LATER #1}
\edef\expanded{\now{a} \later{b} \noexpand\later{c}}
\def\later#1{MUCHLATER #1}

Expect: NOW a LATER b MUCHLATER c.\\
Got: \expanded.

\def\later#1{LATER #1}
\newtoks\tka
\tka={\later{b}}
\edef\expanded{\now{a} \the\tka}
\def\later#1{MUCHLATER #1}

Expect: NOW a MUCHLATER b.\\
Got: \expanded.


\def\later#1{LATER #1}
\newtoks\tka
\tka={\later{b}}
\def\between{BETWEEN }
\edef\expanded{\now{a} \expandafter\between\the\tka}
\def\later#1{MUCHLATER #1}

Expect: NOW a BETWEEN LATER b.\\
Got: \expanded.


\def\later#1{LATER #1}
\newtoks\tka
\tka={\later{b}}
\edef\expanded{\now{a} \expandafter\noexpand\the\tka}
\def\later#1{MUCHLATER #1}

Expect: NOW a MUCHLATER b.\\
Got: \expanded.



\end{document}
