Add a new gtest_discover_tests function to GoogleTest.cmake,
implementing dynamic test discovery (i.e. tests are discovered by
actually running the test executable and asking for the list of
available tests, which is used to dynamically declare the tests) rather
than the source-parsing approach used by gtest_add_tests. Compared to
the source-parsing approach, this has the advantage of being robust
against users declaring tests in unusual ways, and much better support
for advanced features such as parameterized tests.
A unit test, modeled after the TEST_INCLUDE_DIR[S] test, is also
included. Note that the unit test does not actually require that Google
Test is available. The new functionality does not actually depend on
Google Test as such; it only requires that the test executable lists
tests in the expected format when invoked with --gtest_list_tests, which
the unit test can fake readily.
Now has keyword-based arguments (old syntax form is still supported).
Discovered tests can have a prefix and/or suffix added to the test names
and the list of discovered tests is available to the caller. The working
dir can also be set and the dependency on the source files is now
optional instead of mandatory.
Extract the `gtest_add_tests` macro from `FindGTest` into a separate
module. GTest or GoogleTest can be used by a project in a several
different ways, including installed libraries in the system, from an
ExternalProject, or adding the GTest source directory as a sub directory
of the project. As not all of these uses are supported by the FindGTest
module the useful `gtest_add_tests` macro is separated to easily enable
reuse.
Issue: #14151
