Combining sffamily and scshape

Question

According to a relevant comment, one should be able to specify both weights and shapes for each family. Why can I (seemingly) not have small caps with \sffamily?

Minimal example:

\documentclass{article}

\begin{document}
\sffamily\scshape Test
\end{document}

produces the following output:

Answer 1

Imitation of small caps by reducing the uppercase letters can, in some rare cases, give a result slightly above the atrocious level. With Computer Modern Sans Serif such an attempt is doomed to horrible failure, because the heavy strokes are a distinctive feature of the font and you'd be mixing very different strokes between capitals and small capitals. I suggest using spaced all capitals (you get them easily with microtype).

This is an example with Computer Modern, European Modern and Latin Modern.

\documentclass{article}
\usepackage[T1,OT1]{fontenc}
\newcommand{\hsc}[1]{{\footnotesize\MakeUppercase{#1}}}
\begin{document}
\sffamily
T\hsc{his} \hsc{is} F\hsc{ake} S\hsc{mall} C\hsc{aps}

\fontencoding{T1}
T\hsc{his} \hsc{is} F\hsc{ake} S\hsc{mall} C\hsc{aps}

\fontfamily{lmss}
T\hsc{his} \hsc{is} F\hsc{ake} S\hsc{mall} C\hsc{aps}
\end{document}

Apart from the missing kerns, the contrast between the F and the A is too visible and horrible.

Answer 2

There is a version of computer modern with small caps in the sansmathfonts package. You can use it follows:

\documentclass{article}
\usepackage[notmath]{sansmathfonts}
\begin{document}
\sffamily
\textsc{Is This Better Than Fake Small Caps?}
\end{document}

Answer 3

With LuaTeX or XeTeX and fontspec this works out of the box (maybe the font has to support it, but at least with Libertinus):

\documentclass[convert,varwidth]{standalone}
\usepackage{fontspec}

\setmainfont{Libertinus Serif}
\setsansfont{Libertinus Sans}

\begin{document}
Normal Text \\
{\sffamily sffamily Text} \\
{\scshape scshape Text} \\
{\sffamily\scshape sffamily scshape Text} \\
\end{document}

This yields