5 files changed, 30 insertions, 4 deletions
diff --git a/Tests/RunCMake/CMakeLists.txt b/Tests/RunCMake/CMakeLists.txt
index ada913299b..3007660dee 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 20faa946f8..ee3323c0f9 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 7e96b6da57..a4080e3fac 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()
@@ -8,7 +8,7 @@ endif()
 function(run_ctest_timeout CASE_NAME)
   configure_file(${RunCMake_SOURCE_DIR}/TestTimeout.c
                  ${RunCMake_BINARY_DIR}/${CASE_NAME}/TestTimeout.c COPYONLY)
-  run_ctest(${CASE_NAME})
+  run_ctest(${CASE_NAME} ${ARGN})
 endfunction()
 
 run_ctest_timeout(Basic)
@@ -20,3 +20,14 @@ 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.
+  run_ctest_timeout(ZeroOverridesFlag --timeout 2)
+  set(CASE_TEST_PREFIX_CODE "set(CTEST_TEST_TIMEOUT 2)")
+  run_ctest_timeout(ZeroOverridesVar)
+endblock()
diff --git a/Tests/RunCMake/CTestTimeout/ZeroOverridesFlag-stdout.txt b/Tests/RunCMake/CTestTimeout/ZeroOverridesFlag-stdout.txt
new file mode 100644
index 0000000000..746bc218f3
--- /dev/null
+++ b/Tests/RunCMake/CTestTimeout/ZeroOverridesFlag-stdout.txt
@@ -0,0 +1,6 @@
+Test project [^
+]*/Tests/RunCMake/CTestTimeout/ZeroOverridesFlag-build
+    Start 1: TestTimeout
+1/1 Test #1: TestTimeout ......................   Passed +[1-9][0-9.]* sec
++
+100% tests passed, 0 tests failed out of 1
diff --git a/Tests/RunCMake/CTestTimeout/ZeroOverridesVar-stdout.txt b/Tests/RunCMake/CTestTimeout/ZeroOverridesVar-stdout.txt
new file mode 100644
index 0000000000..7192055c3f
--- /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