Hi Peff, On Sat, 26 Nov 2016, Jeff King wrote: > On Sat, Nov 26, 2016 at 01:22:28PM +0100, Johannes Schindelin wrote: > > > In other words, GIT_CONFIG_PARAMETERS is *explicitly scrubbed* from the > > environment when we run our tests (by the code block between the "before" > > and the "after" statements in the diff above). > > Sorry if I wasn't clear. I meant to modify t7800 to run the tests twice, > once with the existing script and once with the builtin. I.e., to set > the variable after test-lib.sh has done its scrubbing, and then use a > loop or similar to go through the tests twice. > > If you want to control it from outside the test script, you'd need > something like: > > if test "$GIT_TEST_DIFFTOOL" = "builtin" That is a bit magic. I first used "GIT_USE_BUILTIN_DIFFTOOL" and it did not work. My name is arguably more correct (see also Jakub's note about "naming is hard"), but yours works because there is a "TEST" substring in it. Ciao, Dscho