Request: Control via environment variables

[iskunk]

Description

It would be useful to support environment variables as an alternative to command-line options when invoking test programs. A good example of this can be seen in googletest's GTEST_FILTER variable, which allows one to specify patterns for test selection/exclusion.

I recently had to deal with the build of xsimd, and its main doctest-based test program (test_xsimd) has a single failing test for me. As I cannot resolve the issue myself, I want to exclude that one specific test for now.

The xsimd build is CMake-based, and I normally invoke the test suite for those via make test. This, in turn, runs ctest, which is what runs test_xsimd. Neither of those layers, as far as I could find, offer a way of passing in a --test-case-exclude=... option to the test program without modifying the source CMake scripts. If there were a e.g. DOCTEST_TEST_CASE_EXCLUDE variable I could set, however, then the solution would be straightforward.

(The syntax would need to be carefully specified, however... the name of the test case at issue includes a space.)

Extra information

I was working with doctest 2.4.11 on Linux.