Our test case relies on the outcome of the family property from freetype though,
it was changed in 2.7.1:
- PCF family names are made more `colourful'; they now include the
foundry and information whether they contain wide characters.
For example, you no longer get `Fixed' but rather `Sony Fixed'
or `Misc Fixed Wide'.
https://bugs.freedesktop.org/show_bug.cgi?id=47704
As file timestamps have only one second granularity, an old cache
file could easily be used when a test took less than 1 second to run.
Just remove the cache directory and its contents before each test is run.
Also, remove mention of the old cache file from the test config file.