From 66fca4ec59c8f063661f6e58026e8118d005203d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Petr=20Men=C5=A1=C3=ADk?= <pemensik@redhat.com>
Date: Wed, 1 Dec 2021 21:18:47 +0100
Subject: [PATCH] Disable catch2 import if already in the system

If CMake can detect catch library, avoid downloading its source and use
system header. It can be used directly from the system automatically.
---
 CMakeLists.txt | 39 ++++++++++++++++++++++++---------------
 1 file changed, 24 insertions(+), 15 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 687d68b..bbbe222 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -290,22 +290,31 @@ endforeach()
 #
 ## Add a rule to download the catch unit test framework
 #
-include(ExternalProject)
-ExternalProject_Add(catch
-  GIT_REPOSITORY "https://lab.louiz.org/louiz/Catch.git"
-  PREFIX "external"
-  UPDATE_COMMAND ""
-  CONFIGURE_COMMAND ""
-  BUILD_COMMAND ""
-  INSTALL_COMMAND ""
-  )
-set_target_properties(catch PROPERTIES EXCLUDE_FROM_ALL TRUE)
-ExternalProject_Get_Property(catch SOURCE_DIR)
-if(NOT EXISTS ${CMAKE_SOURCE_DIR}/tests/catch.hpp)
-  target_include_directories(test_suite
-    PUBLIC "${SOURCE_DIR}/single_include/"
+find_package(Catch2 QUIET)
+if(Catch2_FOUND)
+  add_dependencies(test_suite Catch2::Catch2)
+  get_target_property(CATCH2_INCLUDE Catch2::Catch2 INTERFACE_INCLUDE_DIRECTORIES)
+  target_include_directories(test_suite PUBLIC "${CATCH2_INCLUDE}/catch2")
+  add_library(catch ALIAS Catch2::Catch2)
+  message(STATUS "Catch2 system include dir: ${CATCH2_INCLUDE}")
+else()
+  include(ExternalProject)
+  ExternalProject_Add(catch
+    GIT_REPOSITORY "https://lab.louiz.org/louiz/Catch.git"
+    PREFIX "external"
+    UPDATE_COMMAND ""
+    CONFIGURE_COMMAND ""
+    BUILD_COMMAND ""
+    INSTALL_COMMAND ""
     )
-  add_dependencies(test_suite catch)
+  set_target_properties(catch PROPERTIES EXCLUDE_FROM_ALL TRUE)
+  ExternalProject_Get_Property(catch SOURCE_DIR)
+  if(NOT EXISTS ${CMAKE_SOURCE_DIR}/tests/catch.hpp)
+    target_include_directories(test_suite
+      PUBLIC "${SOURCE_DIR}/single_include/"
+      )
+    add_dependencies(test_suite catch)
+  endif()
 endif()
 
 #
-- 
2.31.1