From 2e0291449bc650be4d54769f292ae2f967efb610 Mon Sep 17 00:00:00 2001
From: Thomas Madlener <thomas.madlener@desy.de>
Date: Fri, 23 Sep 2022 16:10:51 +0200
Subject: [PATCH] Add basic Catch2 setup for unittests

---
 .github/workflows/coverity.yml            |  2 +-
 .github/workflows/linux.yml               |  2 +-
 CMakeLists.txt                            |  1 +
 source/tests/CMakeLists.txt               | 39 +++++++++++++++++++++++
 source/tests/unittests/TestHelixClass.cpp | 20 ++++++++++++
 5 files changed, 62 insertions(+), 2 deletions(-)
 create mode 100644 source/tests/unittests/TestHelixClass.cpp

diff --git a/.github/workflows/coverity.yml b/.github/workflows/coverity.yml
index c3c6f70..ab50693 100644
--- a/.github/workflows/coverity.yml
+++ b/.github/workflows/coverity.yml
@@ -13,7 +13,7 @@ jobs:
     - uses: cvmfs-contrib/github-action-cvmfs@v2
     - uses: aidasoft/run-lcg-view@v3
       with:
-        coverity-cmake-command: 'cmake -C $ILCSOFT/ILCSoft.cmake ..'
+        coverity-cmake-command: 'cmake -C $ILCSOFT/ILCSoft.cmake -DBUILD_TESTING=OFF ..'
         coverity-project: 'iLCSoft%2FMarlinUtil'
         coverity-project-token: ${{ secrets.MARLINUTIL_COVERITY_TOKEN }}
         github-pat: ${{ secrets.READ_COVERITY_IMAGE }}
diff --git a/.github/workflows/linux.yml b/.github/workflows/linux.yml
index 6cbc7ea..a732567 100644
--- a/.github/workflows/linux.yml
+++ b/.github/workflows/linux.yml
@@ -23,7 +23,7 @@ jobs:
         run: |
           mkdir build
           cd build
-          cmake -GNinja -C ${ILCSOFT}/ILCSoft.cmake -DCMAKE_CXX_FLAGS=" -fdiagnostics-color=always " -DINSTALL_DOC=ON ..
+          cmake -GNinja -C ${ILCSOFT}/ILCSoft.cmake -DCMAKE_CXX_FLAGS=" -fdiagnostics-color=always " -DINSTALL_DOC=ON -DUSE_EXTERNAL_CATCH2=OFF ..
           ninja -k0
           ctest --output-on-failure
           ninja install
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 294498a..2799a38 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -120,6 +120,7 @@ SET_SOURCE_FILES_PROPERTIES( "./source/src/ann/kd_pr_search.cpp" PROPERTIES COMP
 #ADD_SHARED_LIBRARY( ${PROJECT_NAME}_ann ${ann_library_sources} )
 #INSTALL_SHARED_LIBRARY( ${PROJECT_NAME}_ann DESTINATION lib )
 
+option(USE_EXTERNAL_CATCH2 "Link against an external Catch2 v3 static library, otherwise build it locally" ON)
 
 IF( BUILD_TESTING )
   ADD_SUBDIRECTORY(source/tests)
diff --git a/source/tests/CMakeLists.txt b/source/tests/CMakeLists.txt
index 11654d0..2aa8ff6 100644
--- a/source/tests/CMakeLists.txt
+++ b/source/tests/CMakeLists.txt
@@ -9,3 +9,42 @@ MACRO( ADD_MARLINUTIL_TEST _name )
 ENDMACRO()
 
 ADD_MARLINUTIL_TEST( testmarlinutil )
+
+#--- Unit test setup. Use existing Catch2 or fetch a suitable version and build it
+if(USE_EXTERNAL_CATCH2)
+  FIND_PACKAGE(Catch2 3.0.0 REQUIRED)
+else()
+  MESSAGE(STATUS "Fetching local copy of Catch2 library for unit-tests...")
+  # Build Catch2 with the default flags, to avoid generating warnings when we
+  # build it
+  SET(CXX_FLAGS_CMAKE_USED ${CMAKE_CXX_FLAGS})
+  SET(CMAKE_CXX_FLAGS ${CXX_FLAGS_CMAKE_DEFAULTS})
+  INCLUDE(FetchContent)
+  fETCHCONTENT_DECLARE(
+    Catch2
+    GIT_REPOSITORY https://github.com/catchorg/Catch2.git
+    GIT_TAG        v3.0.1
+    )
+  FETCHCONTENT_MAKEAVAILABLE(Catch2)
+  set(CMAKE_MODULE_PATH ${Catch2_SOURCE_DIR}/extras ${CMAKE_MODULE_PATH})
+
+  # Disable clang-tidy on external contents
+  SET_TARGET_PROPERTIES(Catch2 PROPERTIES CXX_CLANG_TIDY "")
+
+  # Hack around the fact, that the include directories are not declared as
+  # SYSTEM for the targets defined this way. Otherwise warnings can still occur
+  # in Catch2 code when templates are evaluated (which happens quite a bit)
+  GET_TARGET_PROPERTY(CATCH2_IF_INC_DIRS Catch2 INTERFACE_INCLUDE_DIRECTORIES)
+  SET_TARGET_PROPERTIES(Catch2 PROPERTIES INTERFACE_SYSTEM_INCLUDE_DIRECTORIES "${CATCH2_IF_INC_DIRS}")
+
+  # Reset the flags
+  SET(CMAKE_CXX_FLAGS ${CXX_FLAGS_CMAKE_USED})
+endif()
+
+INCLUDE(Catch)
+
+ADD_EXECUTABLE(unittests unittests/TestHelixClass.cpp)
+TARGET_LINK_LIBRARIES(unittests PUBLIC ${PROJECT_NAME} PRIVATE Catch2::Catch2WithMain)
+CATCH_DISCOVER_TESTS(unittests
+  WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+  )
diff --git a/source/tests/unittests/TestHelixClass.cpp b/source/tests/unittests/TestHelixClass.cpp
new file mode 100644
index 0000000..2986cf4
--- /dev/null
+++ b/source/tests/unittests/TestHelixClass.cpp
@@ -0,0 +1,20 @@
+#include "HelixClass.h"
+#include "HelixClass_double.h"
+
+#include <catch2/catch_approx.hpp>
+#include <catch2/catch_template_test_macros.hpp>
+#include <catch2/catch_test_macros.hpp>
+
+#include <tuple>
+
+TEST_CASE("Example") {
+  REQUIRE(true);                            // obviously
+  REQUIRE(2 == (1 + 1));                    // also quite expected
+  REQUIRE(0.1 + 0.2 == Catch::Approx(0.3)); // The famous IEEE
+}
+
+using HelixTypes = std::tuple<HelixClass, HelixClass_double>;
+
+TEMPLATE_LIST_TEST_CASE("template list example", "", HelixTypes) {
+  REQUIRE(true); // This will be executed for each HelixType
+}