Tests: Extend BuildDepends test to cover OBJECT_DEPENDS

The actual file timestamp dependency is known to not work on
Visual Studio or Xcode generators.  Tolerate such failure for
these generators (Tests/CustomCommand already covers using
OBJECT_DEPENDS to pull a custom command into a target, and
that still works with these generators).

3 files changed, 20 insertions, 0 deletions

diff --git a/Tests/BuildDepends/Project/CMakeLists.txt b/Tests/BuildDepends/Project/CMakeLists.txt
index 0db39c5..3aa57fc 100644
--- a/Tests/BuildDepends/Project/CMakeLists.txt
+++ b/Tests/BuildDepends/Project/CMakeLists.txt
@@ -182,3 +182,15 @@ if(TEST_MULTI3)
   set_property(SOURCE multi3-real.txt multi3-dummy.txt PROPERTY SYMBOLIC 1)
   add_custom_target(multi3 ALL DEPENDS multi3-real.txt)
 endif()
+
+add_executable(object_depends object_depends.cxx)
+set_property(SOURCE object_depends.cxx PROPERTY OBJECT_DEPENDS
+  ${CMAKE_CURRENT_BINARY_DIR}/object_depends.txt)
+add_custom_target(object_depends_check ALL
+  COMMAND ${CMAKE_COMMAND}
+   -Dexe=$<TARGET_FILE:object_depends>
+   -Dout=${CMAKE_CURRENT_BINARY_DIR}/object_depends_check.txt
+   -Dtxt=${CMAKE_CURRENT_BINARY_DIR}/object_depends.txt
+   -P ${CMAKE_CURRENT_SOURCE_DIR}/object_depends_check.cmake
+  )
+add_dependencies(object_depends_check object_depends)
diff --git a/Tests/BuildDepends/Project/object_depends.cxx b/Tests/BuildDepends/Project/object_depends.cxx
new file mode 100644
index 0000000..76e8197
--- /dev/null
+++ b/Tests/BuildDepends/Project/object_depends.cxx
@@ -0,0 +1 @@
+int main() { return 0; }
diff --git a/Tests/BuildDepends/Project/object_depends_check.cmake b/Tests/BuildDepends/Project/object_depends_check.cmake
new file mode 100644
index 0000000..e009892
--- /dev/null
+++ b/Tests/BuildDepends/Project/object_depends_check.cmake
@@ -0,0 +1,7 @@
+if(NOT EXISTS "${txt}" OR NOT EXISTS "${exe}")
+  file(REMOVE "${out}")
+elseif("${exe}" IS_NEWER_THAN "${txt}")
+  file(WRITE "${out}" "1\n")
+else()
+  file(WRITE "${out}" "0\n")
+endif()