Re: [PATCH/RFC] t9500-*.sh: Fix highlight test hang on Linux Mint

Ramsay Jones [off-list ref] writes:

In order to allow the user to specify the correct tool, introduce
the GIT_TEST_HIGHLIGHT_BIN variable. Also, add '</dev/null' to the
command line of the highlight invocation; this avoids hanging the
test if the filter script is used nonetheless.

gitweb/Makefile seems to have a rule to set this to a custom
location, though.  Why do we need a special test-only location?  If
the user wants the right one during the test, wouldn't the final
build and install also want to use the same "right one" that is not
just a generic 'highlight' that does not say which path it resides
at?

So I think forcing the testers to say the same thing twice like this
patch does is a good way forward.  Add a mechanism to allow outside
world to ask which "highlight" gitweb/Makefile was told to use, use
that mechanism to learn the value of HIGHLIGHT_BIN to check if the
binary is usable for the test, or something perhaps?

The killing of the input is independently a good idea, I think.