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)

.circleci/config.yml

@@ -23,7 +23,7 @@ jobs:
           command: |
             mkdir bin
             cd bin
-            cmake ../ -DWITH_WARNINGS=1 -DWITH_COREDEBUG=0 -DUSE_COREPCH=1 -DUSE_SCRIPTPCH=1 -DTOOLS=1 -DSCRIPTS=static -DSERVERS=1 -DNOJEM=0 -DCMAKE_BUILD_TYPE=Debug -DCMAKE_C_FLAGS="-Werror" -DCMAKE_CXX_FLAGS="-Werror" -DCMAKE_C_FLAGS_DEBUG="-DNDEBUG" -DCMAKE_CXX_FLAGS_DEBUG="-DNDEBUG" -DCMAKE_INSTALL_PREFIX=check_install
+            cmake ../ -DWITH_WARNINGS=1 -DWITH_COREDEBUG=0 -DUSE_COREPCH=1 -DUSE_SCRIPTPCH=1 -DTOOLS=1 -DSCRIPTS=static -DSERVERS=1 -DNOJEM=0 -DCMAKE_BUILD_TYPE=Debug -DCMAKE_C_FLAGS="-Werror" -DCMAKE_CXX_FLAGS="-Werror" -DCMAKE_C_FLAGS_DEBUG="-DNDEBUG" -DCMAKE_CXX_FLAGS_DEBUG="-DNDEBUG" -DCMAKE_INSTALL_PREFIX=check_install -DBUILD_TESTING=1
             cd ..
       - run:
           name: SQL checks
@@ -44,7 +44,15 @@ jobs:
           command: |
             cd bin
             make -j 4 -k && make install
-            cd check_install/bin
+      - run:
+          name: Unit tests
+          command: |
+            cd bin
+            make test
+      - run:
+          name: Check executables
+          command: |
+            cd bin/check_install/bin
             ./bnetserver --version
             ./worldserver --version
       - setup_remote_docker: