\input plain.tex
\input pdftexconfig.tex
\input pdftexmagfix.tex

\pdfmapline{+dummy-space <dummy-space.pfb}
\pdfglyphtounicode{space}{0020}
\pdfcompresslevel=0
\pdfobjcompresslevel=0

Text with no interword spaces.

\pdfinterwordspaceon

Switch to text with faked interword spaces.

\pdfinterwordspaceoff

Back to text with no interword \pdffakespace spaces.

% Test of \pdffakespace in vertical mode
\pdffakespace

% Test of \pdffakespace in math mode
$a\pdffakespace b$

Back to text with no interword \pdffakespace\pdffakespace spaces.

% Test of \pdffakespace in vertical mode
\pdffakespace
\pdffakespace

% Test of \pdffakespace in math mode
$a\pdffakespace \pdffakespace b$
\bye