CMAKE_TEST_BUILD_DEPENDS

Added in version 4.4.

Enable test_prep/<name> build targets for tests added by add_test() when using the Ninja Generators, FASTBuild, or Makefile Generators.

Added in version 4.5: FASTBuild and the Makefile Generators gained support for test_prep/<name> targets.

When this variable is set to a true value, CMake generates a test_prep/<name> target for each eligible test and a test_prep/all target for all such tests. Building these targets ensures the test executable, targets referenced by test command generator expressions, and explicit BUILD_DEPENDS entries are up-to-date before the test runs.

Added in version 4.5: Modules may also extend test_prep/all with directory-scoped dependencies via the CMAKE_TEST_BUILD_DEPENDS directory property.

Tests whose names are not valid target names are excluded from this behavior. If multiple tests in different directories share the same name, their dependencies are merged into a single test_prep/<name> target.

With the Makefile Generators, a BUILD_DEPENDS file is built by building the target whose build produces it. A generated file that is not the unique output of a single target is reported with a warning, and a test whose name contains a : character is excluded because it cannot be expressed as a Makefile target.