4 files changed, 22 insertions, 3 deletions
diff --git a/Tests/RunCMake/CMakeLists.txt b/Tests/RunCMake/CMakeLists.txt
index ada9132..3007660 100644
--- a/Tests/RunCMake/CMakeLists.txt
+++ b/Tests/RunCMake/CMakeLists.txt
@@ -562,7 +562,10 @@ add_RunCMake_test(alias_targets)
 add_RunCMake_test(InterfaceLibrary)
 add_RunCMake_test(no_install_prefix)
 add_RunCMake_test(configure_file)
-add_RunCMake_test(CTestTimeout -DTIMEOUT=${CTestTestTimeout_TIME})
+if(CTestTestTimeout_TIME)
+  set(CTestTimeout_ARGS -DTIMEOUT=${CTestTestTimeout_TIME})
+endif()
+add_RunCMake_test(CTestTimeout)
 add_RunCMake_test(CTestTimeoutAfterMatch)
 if(CMake_TEST_CUDA)
   add_RunCMake_test(CUDA_architectures)
diff --git a/Tests/RunCMake/CTestTimeout/CMakeLists.txt.in b/Tests/RunCMake/CTestTimeout/CMakeLists.txt.in
index 20faa94..ee3323c 100644
--- a/Tests/RunCMake/CTestTimeout/CMakeLists.txt.in
+++ b/Tests/RunCMake/CTestTimeout/CMakeLists.txt.in
@@ -4,7 +4,7 @@ include(CTest)
 
 add_executable(TestTimeout TestTimeout.c)
 
-if(NOT TIMEOUT)
+if(NOT DEFINED TIMEOUT)
   set(TIMEOUT 4)
 endif()
 target_compile_definitions(TestTimeout PRIVATE TIMEOUT=${TIMEOUT})
diff --git a/Tests/RunCMake/CTestTimeout/RunCMakeTest.cmake b/Tests/RunCMake/CTestTimeout/RunCMakeTest.cmake
index 7e96b6d..e55ba27 100644
--- a/Tests/RunCMake/CTestTimeout/RunCMakeTest.cmake
+++ b/Tests/RunCMake/CTestTimeout/RunCMakeTest.cmake
@@ -1,6 +1,6 @@
 include(RunCTest)
 
-if(NOT TIMEOUT)
+if(NOT DEFINED TIMEOUT)
   # Give the process time to load and start running.
   set(TIMEOUT 4)
 endif()
@@ -20,3 +20,13 @@ if(UNIX)
   run_ctest_timeout(Fork)
   unset(CASE_CMAKELISTS_SUFFIX_CODE)
 endif()
+
+block()
+  # An explicit zero TIMEOUT test property means "no timeout".
+  set(TIMEOUT 0)
+  # The test sleeps for 4 seconds longer than the TIMEOUT value.
+  # Set a default timeout to less than that so that the test will
+  # timeout if the zero TIMEOUT does not suppress it.
+  set(CASE_TEST_PREFIX_CODE "set(CTEST_TEST_TIMEOUT 2)")
+  run_ctest_timeout(ZeroOverridesVar)
+endblock()
diff --git a/Tests/RunCMake/CTestTimeout/ZeroOverridesVar-stdout.txt b/Tests/RunCMake/CTestTimeout/ZeroOverridesVar-stdout.txt
new file mode 100644
index 0000000..7192055
--- /dev/null
+++ b/Tests/RunCMake/CTestTimeout/ZeroOverridesVar-stdout.txt
@@ -0,0 +1,6 @@
+Test project [^
+]*/Tests/RunCMake/CTestTimeout/ZeroOverridesVar-build
+    Start 1: TestTimeout
+1/1 Test #1: TestTimeout ......................   Passed +[1-9][0-9.]* sec
++
+100% tests passed, 0 tests failed out of 1