[test] Implement Sigterm-equivalent test for Unix

Fixes #13300

Author: ferdymercury

io/io/test/CMakeLists.txt

@@ -5,7 +5,7 @@
 # For the list of contributors see $ROOTSYS/README/CREDITS.
 
 ROOT_ADD_GTEST(RRawFile RRawFile.cxx LIBRARIES RIO)
-ROOT_ADD_GTEST(TFile TFileTests.cxx LIBRARIES RIO)
+ROOT_ADD_GTEST(TFile TFileTests.cxx LIBRARIES RIO Hist)
 ROOT_ADD_GTEST(TBufferFile TBufferFileTests.cxx LIBRARIES RIO)
 ROOT_ADD_GTEST(TBufferMerger TBufferMerger.cxx LIBRARIES RIO Imt Tree)
 ROOT_ADD_GTEST(TBufferJSON TBufferJSONTests.cxx LIBRARIES RIO)

io/io/test/TFileTests.cxx

@@ -1,10 +1,12 @@
 #include <memory>
 #include <vector>
 #include <string>
+#include <csignal>
 
 #include "gtest/gtest.h"
 
 #include "TFile.h"
+#include "TH1I.h"
 #include "TMemFile.h"
 #include "TDirectory.h"
 #include "TKey.h"
@@ -251,3 +253,31 @@ TEST(TFile, WalkTKeys)
    EXPECT_EQ(it->fKeyName, kLongerKey);
    EXPECT_EQ(it->fClassName, "string");
 }
+
+void handle_sigterm(int signum)
+{
+   terminated = 1;
+   std::cout << "handled signal " << strsignal(signum) << " on PID " << getpid() << std::endl;
+}
+
+// https://github.com/root-project/root/issues/13300
+TEST(TFile, Sigterm)
+{
+   auto filename = "out13300.root";
+   {
+      TFile file(filename, "RECREATE");
+      file.mkdir("subdir")->cd();
+      TH1I hist("h", "h", 10, 0., 1.);
+      hist.Fill(0.4);
+      // Since the real behavior is save+close+crash which would make the test fail,
+      // rather than calling directly std::raise(SIGTERM),
+      // we emulate the response to SIGTERM in TerminalConfigUnix before crash:
+      TROOT::WriteCloseAllFiles();
+      TROOT::CleanUpROOTAtExit();
+   }
+   {
+      TFile file(filename, "READ");
+      ASSERT_EQ(file.Get<TH1I>("subdir/h")->GetBinContent(5), 1);
+   }
+   gSystem->Unlink(filename);
+}