tests: If system Catch2 is the same or newer, use it

... it may contain additional fixes relevant to the given OS and also
issue a warning if there is a newer version, so that we will be notified
to update the bundled one.

tests/CMakeLists.txt

@@ -17,19 +17,48 @@ add_custom_target(check COMMAND ${CMAKE_CTEST_COMMAND} ${CTEST_OPTS}
                         USES_TERMINAL)
 
 # --------------------------------------------------
-# precompile Catch2 main
+# Catch2
 # --------------------------------------------------
+
+# version of bundled Catch2
+set(CATCH_VERSION 2.13.5)
+
+# Catch2 main
 add_library(catch-main OBJECT catch-main.cpp)
 
+# If we can find the same version or newer, use it as it may contain
+# additional fixes relevant to the given OS
+find_package(Catch2 ${CATCH_VERSION} QUIET CONFIG)
+if(Catch2_FOUND)
+    message(STATUS "Found Catch2 (found version \"${Catch2_VERSION}\")")
+    # Issue a warning if there is a newer version, so that we will be notified
+    # to update the bundled one.
+    if(${CATCH_VERSION} VERSION_GREATER ${Catch2_FOUND})
+        message(WARNING
+            "The bundled Catch2 seems to be outdated: ${CATCH_VERSION}\n"
+            "Please report this to our issue tracker. Thank you!")
+    endif()
+
+    # use correct include directories
+    target_link_libraries(catch-main PRIVATE Catch2::Catch2)
+else()
+    include_directories(${CMAKE_CURRENT_SOURCE_DIR})
+endif()
+
 macro(add_catch_test TEST_FILE)
     if (NOT EXISTS "${CMAKE_CURRENT_LIST_DIR}/${TEST_FILE}")
         message(FATAL_ERROR "Test '${TEST_FILE}' does not exist!")
     endif()
     get_filename_component(TEST ${TEST_FILE} NAME_WE)
 
-    add_executable(${TEST} ${TEST_FILE} $<TARGET_OBJECTS:catch-main>)
+    add_executable(${TEST} ${TEST_FILE})
     add_test(${TEST} ${TEST})
     add_dependencies(check ${TEST})
+    target_link_libraries(${TEST} PRIVATE $<TARGET_OBJECTS:catch-main>)
+
+    if(Catch2_FOUND)
+        target_link_libraries(${TEST} PRIVATE Catch2::Catch2)
+    endif()
 endmacro()
 
 # --------------------------------------------------

tests/adt-test.cpp

@@ -1,4 +1,4 @@
-#include "catch.hpp"
+#include <catch2/catch.hpp>
 
 #include "dg/ADT/Queue.h"
 #include "dg/ADT/Bitvector.h"

tests/bitvector-test.cpp

@@ -1,4 +1,4 @@
-#include "catch.hpp"
+#include <catch2/catch.hpp>
 
 #include <random>
 #include <set>

tests/catch-main.cpp

@@ -1,2 +1,2 @@
 #define CATCH_CONFIG_MAIN
-#include "catch.hpp"
+#include <catch2/catch.hpp>

tests/disjunctive-intervals-map-test.cpp

@@ -1,4 +1,4 @@
-#include "catch.hpp"
+#include <catch2/catch.hpp>
 
 #include <random>
 #include <sstream>

tests/llvm-dg-test.cpp

@@ -1,4 +1,4 @@
-#include "catch.hpp"
+#include <catch2/catch.hpp>
 
 #include "dg/llvm/LLVMDependenceGraph.h"
 #include "dg/DFS.h"

tests/nodes-walk-test.cpp

@@ -1,4 +1,4 @@
-#include "catch.hpp"
+#include <catch2/catch.hpp>
 
 #include <dg/NodesWalk.h>
 #include <dg/ADT/Queue.h>

tests/numbers-set-test.cpp

@@ -1,4 +1,4 @@
-#include "catch.hpp"
+#include <catch2/catch.hpp>
 
 #include <set>
 

tests/points-to-set-test.cpp

@@ -1,4 +1,4 @@
-#include "catch.hpp"
+#include <catch2/catch.hpp>
 
 #include "dg/PointerAnalysis/PSNode.h"
 #include "dg/PointerAnalysis/PointerGraph.h"

tests/points-to-test.cpp

@@ -1,4 +1,4 @@
-#include "catch.hpp"
+#include <catch2/catch.hpp>
 
 #include "dg/PointerAnalysis/PointerGraph.h"
 #include "dg/PointerAnalysis/PointerAnalysisFI.h"

tests/rdmap-test.cpp

@@ -1,4 +1,4 @@
-#include "catch.hpp"
+#include <catch2/catch.hpp>
 
 #include <random>
 #include <cassert>

tests/readwritegraph-test.cpp

@@ -1,4 +1,4 @@
-#include "catch.hpp"
+#include <catch2/catch.hpp>
 
 #include "dg/ReadWriteGraph/ReadWriteGraph.h"
 

tests/thread-regions-test.cpp

@@ -1,4 +1,4 @@
-#include "catch.hpp"
+#include <catch2/catch.hpp>
 
 #include "dg/llvm/PointerAnalysis/PointerAnalysis.h"
 #include "dg/PointerAnalysis/PointerAnalysisFI.h"