CTest: adopt std::chrono::system_clock

After the refactor to make CTest use std::chrono::steady_clock for the
keeping of time for test duration, there are still references to
cmSystemTools::GetTime() left.
To further adopt std::chrono for time related activities, this commit
changes those remaining references to std::chrono::system_clock::now()
calls and alters the storage from either unsigned int or double to
std::chrono::system_clock::time_point.

For ease of conversion, a converter method is added to cmXMLWriter that
converts from a std::chrono::system_clock::time_point to the number of
seconds since the UN*X epoch as that is expected behaviour. This means
no more casts as required.

Functionally should be no difference as the system_clock is implemented
in the same terms.

1 files changed, 2 insertions, 2 deletions

diff --git a/Source/CTest/cmCTestTestHandler.cxx b/Source/CTest/cmCTestTestHandler.cxx
index b814e35..e7c719c 100644
--- a/Source/CTest/cmCTestTestHandler.cxx
+++ b/Source/CTest/cmCTestTestHandler.cxx
@@ -1204,7 +1204,7 @@ void cmCTestTestHandler::ProcessDirectory(std::vector<std::string>& passed,
 {
   this->ComputeTestList();
   this->StartTest = this->CTest->CurrentTime();
-  this->StartTestTime = static_cast<unsigned int>(cmSystemTools::GetTime());
+  this->StartTestTime = std::chrono::system_clock::now();
   auto elapsed_time_start = std::chrono::steady_clock::now();
 
   cmCTestMultiProcessHandler* parallel = this->CTest->GetBatchJobs()
@@ -1271,7 +1271,7 @@ void cmCTestTestHandler::ProcessDirectory(std::vector<std::string>& passed,
   }
   delete parallel;
   this->EndTest = this->CTest->CurrentTime();
-  this->EndTestTime = static_cast<unsigned int>(cmSystemTools::GetTime());
+  this->EndTestTime = std::chrono::system_clock::now();
   this->ElapsedTestingTime =
     std::chrono::steady_clock::now() - elapsed_time_start;
   *this->LogFile << "End testing: " << this->CTest->CurrentTime() << std::endl;