[lltx] fontspec test suite

[Will Robertson]

Dear all,

I've now added a test suite to fontspec. It currently contains no tests :) -- besides some examples. Please try it out! You'll need ImageMagick and an environment that can deal with Makefiles and so on. (I *think* all TeX distributions come with ImageMagick these days, but I might be wrong.)

The only step required, I hope, is to run `make check` after you've grabbed the files from <http://github.com/wspr/fontspec>. Now that I mention it, you might need to manually create a build/ directory.

Three types of tests are supported with the following naming scheme:

  F001a - compiles with both xelatex and lualatex and checks the output of both
  L001a - compiles with lualatex only
  X001a - compiles with xelatex only

It uses a visual diff of the compiled PDFs against a reference PDF in the testsuite/ directory. There's a "fuzz" factor incorporated to hopefully reduce the occurrence of false negatives.

I'm interested to see

(a) if the test suite actually functions (my shell scripting isn't so hot)
(b) if the test suite actually passes (rounding errors might be too large)

If (b) doesn't work, then I'll remove the ".safe.pdf" files from the repository, and the test suite can be used simply as a regression suite for each developer.

Once we know that it works, it'll be time to fill it up with tests. I'm pretty much out of time for fontspec for the foreseeable future. But there's a bug or two that I just discover that need to be fixed, so I guess I'll just have to find the time.

-- Will