Gdtyjr

I'm certain this must be a duplicate as there are lots of very similar questions, but none of the answers I can find work for me.

I have a set of .otf font files (one each for the regular, italic, bold and bold italic versions) which I want to use as the default font in a XeLaTeX document. I've tried lots of ways of loading them, but here's a concrete example:

documentclassarticle
usepackagefontspec
setmainfontHelveticaNeueLTPro[
 Path = /home/richard/,
 UprightFont = *-Roman,
 BoldFont = *-Bold,
 ItalicFont = *-Italic,
 BoldItalicFont = *-BoldItalic,
 Extension = .otf]

begindocument
Test
enddocument

At the moment, this test.tex file plus the four .otf files are in my home directory (/home/richard/):

richard@fannich:~$ ls -l *.otf *.tex
-rw-r--r-- 1 richard richard 21608 Mar 14 21:44 HelveticaNeueLTPro-BdIt.otf
-rw-r--r-- 1 richard richard 22776 Mar 14 21:44 HelveticaNeueLTPro-Bd.otf
-rw-r--r-- 1 richard richard 17404 Mar 14 21:44 HelveticaNeueLTPro-It.otf
-rw-r--r-- 1 richard richard 26936 Mar 14 21:44 HelveticaNeueLTPro-Roman.otf
-rw-r--r-- 1 richard richard 290 Mar 14 21:57 test.tex

When I run xelatex test, I get the following error:

(/usr/share/texlive/texmf-dist/tex/latex/graphics-def/xetex.def)))))kpathsea:make_tex: Invalid fontname `[/home/richard/HelveticaNeueLTPro-Roman.otf]/OT', contains '['

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!
! fontspec error: "font-not-found"
! 
! The font "HelveticaNeueLTPro-Roman" cannot be found.
! 
! See the fontspec documentation for further information.
! 
! For immediate help type H <return>.
!............................................... 

l.9 Extension = .otf]

So far as I can see, I've done exactly what is described in this answer. I've also tried putting the path in braces per this answer, though I think that's only necessary if you spaces or other special characters in the path. I've also tried using the old setmainfont syntax per this answer, though my fontspec package seems to be from 2017 (the TexLive packages are the Debian ones labelled 2016.20170123-5). I've also tried using xltxtra instead of fontspec per this answer. I've tried removing the Extension = .otf and appending .otf to each font name. I've tried removing the Path parameter as it's in the local directors. I've tried just putting a bare setmainfontHelveticaNeueLTPro-Roman.otf. None of these change the error I see.

Any suggestions? One thing I can't do is install the fonts as root.