CompileDefinitions: Add unit test for setting empty content.

Tests/RunCMake/CMakeLists.txt

@@ -143,6 +143,7 @@ add_RunCMake_test(Swift)
 add_RunCMake_test(TargetObjects)
 add_RunCMake_test(TargetSources)
 add_RunCMake_test(find_dependency)
+add_RunCMake_test(CompileDefinitions)
 add_RunCMake_test(CompileFeatures)
 add_RunCMake_test(WriteCompilerDetectionHeader)
 if(NOT WIN32)

Tests/RunCMake/CompileDefinitions/CMakeLists.txt

@@ -0,0 +1,3 @@
+cmake_minimum_required(VERSION 3.3)
+project(${RunCMake_TEST} NONE)
+include(${RunCMake_TEST}.cmake)

Tests/RunCMake/CompileDefinitions/RunCMakeTest.cmake

@@ -0,0 +1,3 @@
+include(RunCMake)
+
+run_cmake(SetEmpty)

Tests/RunCMake/CompileDefinitions/SetEmpty-result.txt

@@ -0,0 +1 @@
+0

Tests/RunCMake/CompileDefinitions/SetEmpty-stderr.txt

@@ -0,0 +1,3 @@
+RESULT1=A;;B
+RESULT2=
+RESULT3=-DBAR

Tests/RunCMake/CompileDefinitions/SetEmpty.cmake

@@ -0,0 +1,12 @@
+
+set_property(DIRECTORY PROPERTY COMPILE_DEFINITIONS A "" B)
+get_property(result DIRECTORY PROPERTY COMPILE_DEFINITIONS)
+message("RESULT1=${result}")
+
+set_property(DIRECTORY PROPERTY COMPILE_DEFINITIONS)
+get_property(result DIRECTORY PROPERTY COMPILE_DEFINITIONS)
+message("RESULT2=${result}")
+
+set_property(DIRECTORY PROPERTY COMPILE_DEFINITIONS -DBAR)
+get_property(result DIRECTORY PROPERTY COMPILE_DEFINITIONS)
+message("RESULT3=${result}")