dep: Add catch2 unit test framework and wire it up

To enable the test suite, make sure to configure CMake with -DBUILD_TESTING=1 , since it is disabled by default. The catch2 dependency will be downloaded during configure time.

Also add a new target "tests-common", which includes unit tests for the "common" project. To finally run the tests use the "test" target.

CircleCI: Run unit tests
(cherry picked from commit 6a28ee7b2a4269aa7e43265d1cd0067537e3e883)

cmake/options.cmake

@@ -50,4 +50,5 @@ option(WITH_COREDEBUG   "Include additional debug-code in core"
 set(WITH_SOURCE_TREE    "hierarchical" CACHE STRING "Build the source tree for IDE's.")
 set_property(CACHE WITH_SOURCE_TREE PROPERTY STRINGS no flat hierarchical hierarchical-folders)
 option(WITHOUT_GIT      "Disable the GIT testing routines"                            0)
+option(BUILD_TESTING    "Build test suite" 0)
 

cmake/showoptions.cmake

@@ -35,6 +35,12 @@ else()
   message("* Build map/vmap tools   : No")
 endif()
 
+if(BUILD_TESTING)
+  message("* Build unit tests       : Yes")
+else()
+  message("* Build unit tests       : No (default)")
+endif()
+
 if( USE_COREPCH )
   message("* Build core w/PCH       : Yes (default)")
 else()