GoogleTest: Add timeout to discovery

Add a TIMEOUT option to gtest_discover_tests. This provides a
work-around in case a test goes out to lunch, rather than causing the
build to simply hang. (Although this is still a problem with the user's
project, hanging the build is not cool, especially in the case of
automatically running CI builds. It is much preferred that the build
should actively fail in this case, and it is trivially easy for us to
implement that.)

Modules/GoogleTest.cmake

@@ -217,6 +217,14 @@ same as the Google Test name (i.e. ``suite.testcase``); see also
     executable is being used in multiple calls to ``gtest_discover_tests()``.
     Note that this variable is only available in CTest.
 
+  ``TIMEOUT num``
+    Specifies how long (in seconds) CMake will wait for the test to enumerate
+    available tests.  If the test takes longer than this, discovery (and your
+    build) will fail.  Most test executables will enumerate their tests very
+    quickly, but under some exceptional circumstances, a test may require a
+    longer timeout.  The default is 5.  See also the ``TIMEOUT`` option of
+    :command:`execute_process`.
+
 #]=======================================================================]
 
 #------------------------------------------------------------------------------
@@ -349,7 +357,7 @@ function(gtest_discover_tests TARGET)
   cmake_parse_arguments(
     ""
     "NO_PRETTY_TYPES;NO_PRETTY_VALUES"
-    "TEST_PREFIX;TEST_SUFFIX;WORKING_DIRECTORY;TEST_LIST"
+    "TEST_PREFIX;TEST_SUFFIX;WORKING_DIRECTORY;TEST_LIST;TIMEOUT"
     "EXTRA_ARGS;PROPERTIES"
     ${ARGN}
   )
@@ -360,6 +368,9 @@ function(gtest_discover_tests TARGET)
   if(NOT _TEST_LIST)
     set(_TEST_LIST ${TARGET}_TESTS)
   endif()
+  if(NOT _TIMEOUT)
+    set(_TIMEOUT 5)
+  endif()
 
   get_property(
     has_counter
@@ -407,6 +418,7 @@ function(gtest_discover_tests TARGET)
             -D "NO_PRETTY_VALUES=${_NO_PRETTY_VALUES}"
             -D "TEST_LIST=${_TEST_LIST}"
             -D "CTEST_FILE=${ctest_tests_file}"
+            -D "TEST_DISCOVERY_TIMEOUT=${_TIMEOUT}"
             -P "${_GOOGLETEST_DISCOVER_TESTS_SCRIPT}"
     VERBATIM
   )

Modules/GoogleTestAddTests.cmake

@@ -30,6 +30,7 @@ if(NOT EXISTS "${TEST_EXECUTABLE}")
 endif()
 execute_process(
   COMMAND ${TEST_EXECUTOR} "${TEST_EXECUTABLE}" --gtest_list_tests
+  TIMEOUT ${TEST_DISCOVERY_TIMEOUT}
   OUTPUT_VARIABLE output
   RESULT_VARIABLE result
 )

Tests/RunCMake/GoogleTest/GoogleTest-timeout-result.txt

@@ -0,0 +1 @@
+[^0]

Tests/RunCMake/GoogleTest/GoogleTest-timeout-stdout.txt

@@ -0,0 +1,7 @@
+( *|[0-9]+>)CMake Error at .*GoogleTestAddTests.cmake:[0-9]+ \(message\):
+( *|[0-9]+>)  Error running test executable.
+?( *|[0-9]+>)
+( *|[0-9]+>)    Path: '.*timeout_test(\.exe)?'
+( *|[0-9]+>)    Result: Process terminated due to timeout
+( *|[0-9]+>)    Output:
+( *|[0-9]+>)     +

Tests/RunCMake/GoogleTest/GoogleTest.cmake

@@ -21,3 +21,9 @@ gtest_discover_tests(
   EXTRA_ARGS how now "\"brown\" cow"
   PROPERTIES LABELS TEST2
 )
+
+add_executable(timeout_test timeout_test.cpp)
+
+gtest_discover_tests(
+  timeout_test
+)

Tests/RunCMake/GoogleTest/RunCMakeTest.cmake

@@ -9,18 +9,32 @@ function(run_GoogleTest)
   endif()
   file(REMOVE_RECURSE "${RunCMake_TEST_BINARY_DIR}")
   file(MAKE_DIRECTORY "${RunCMake_TEST_BINARY_DIR}")
+
   run_cmake(GoogleTest)
+
   run_cmake_command(GoogleTest-build
     ${CMAKE_COMMAND}
     --build .
     --config Debug
+    --target fake_gtest
   )
+
+  set(RunCMake_TEST_OUTPUT_MERGE 1)
+  run_cmake_command(GoogleTest-timeout
+    ${CMAKE_COMMAND}
+    --build .
+    --config Debug
+    --target timeout_test
+  )
+  set(RunCMake_TEST_OUTPUT_MERGE 0)
+
   run_cmake_command(GoogleTest-test1
     ${CMAKE_CTEST_COMMAND}
     -C Debug
     -L TEST1
     --no-label-summary
   )
+
   run_cmake_command(GoogleTest-test2
     ${CMAKE_CTEST_COMMAND}
     -C Debug

Tests/RunCMake/GoogleTest/timeout_test.cpp

@@ -0,0 +1,15 @@
+#if defined(_WIN32)
+#include <windows.h>
+#else
+#include <unistd.h>
+#endif
+
+int main()
+{
+#if defined(_WIN32)
+  Sleep(10000);
+#else
+  sleep(10);
+#endif
+  return 0;
+}