Do not add tests if project is included via add_subdirectory/FetchContent (#8)

Author: traversaro

CMakeLists.txt

@@ -15,6 +15,19 @@ project(serial_cpp VERSION ${SERIAL_CPP_MAJOR_VERSION}.${SERIAL_CPP_MINOR_VERSIO
 option(BUILD_SHARED_LIBS "Build libraries as shared as opposed to static" OFF)
 option(BUILD_TESTING "Build tests" OFF)
 option(serial_cpp_INSTALL "Enable generation of serial_cpp install targets" ON)
+mark_as_advanced(serial_cpp_INSTALL)
+option(serial_cpp_FORCE_RESPECT_BUILD_TESTING "If also BUILD_TESTING is ON, enable tests even if project was included via add_subdirectory/FetchContent" OFF)
+mark_as_advanced(serial_cpp_FORCE_RESPECT_BUILD_TESTING)
+
+# Detect if project is top level or not (fall back for CMake < 3.21)
+if(CMAKE_VERSION VERSION_LESS "3.21.0")
+    if(CMAKE_CURRENT_SOURCE_DIR STREQUAL CMAKE_SOURCE_DIR)
+        set(PROJECT_IS_TOP_LEVEL ON)
+    else()
+        set(PROJECT_IS_TOP_LEVEL OFF)
+    endif()
+endif()
+
 
 # Default install locations
 include(GNUInstallDirs)
@@ -120,6 +133,10 @@ endif()
 
 ## Tests
 include(CTest)
-if(BUILD_TESTING)
+# Tests are enabled if BUILD_TESTING is enabled and PROJECT_IS_TOP_LEVEL is ON,
+# or if serial_cpp_FORCE_RESPECT_BUILD_TESTING is ON, so if you include the project
+# via FetchContent or add_subdirectory and if you want to compile tests, you
+# need to set both BUILD_TESTING and serial_cpp_FORCE_RESPECT_BUILD_TESTING to ON
+if(BUILD_TESTING OR (PROJECT_IS_TOP_LEVEL OR serial_cpp_FORCE_RESPECT_BUILD_TESTING))
     add_subdirectory(tests)
 endif()

package.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 <package>
   <name>serial_cpp</name>
-  <version>1.3.1</version>
+  <version>1.3.2</version>
   <description>
     serial_cpp is a cross-platform, simple to use library for using serial ports on computers.
     This library provides a C++, object oriented interface for interacting with RS-232