Enable stressGUI tests with xvfb

If xvfb-run detected on the system,
use it to run stressGUI test.
First create ref file and then check that it match.

Prinout log information when generating ref file in stressGUI -
otherwise missing info if something went wrong

Author: linev

test/CMakeLists.txt

@@ -196,6 +196,21 @@ ROOT_ADD_TEST(test-stresshistogram-interpreted COMMAND ${root_exe} -b -q ${CMAKE
 #--stressGUI---------------------------------------------------------------------------------------
 if(asimage)
   ROOT_EXECUTABLE(stressGUI stressGUI.cxx LIBRARIES Gui Recorder GuiHtml ASImageGui)
+
+  find_program(XVFB_RUN_EXECUTABLE NAMES xvfb-run)
+
+  if(XVFB_RUN_EXECUTABLE)
+    ROOT_ADD_TEST(test-stressgui-ref
+                  COMMAND ${XVFB_RUN_EXECUTABLE} -a -s "-ac -screen 0 1024x768x24" ./stressGUI -ref
+                  FIXTURES_SETUP fixtures-test-stressgui
+                  FAILREGEX "FAILED|Error in"
+                  LABELS longtest)
+    ROOT_ADD_TEST(test-stressgui-xvfb
+                  COMMAND ${XVFB_RUN_EXECUTABLE} -a -s "-ac -screen 0 1024x768x24" ./stressGUI
+                  FIXTURES_REQUIRED fixtures-test-stressgui
+                  FAILREGEX "FAILED|Error in"
+                  LABELS longtest)
+  endif()
 endif()
 
 #--stressSpectrum----------------------------------------------------------------------------------

test/stressGUI.cxx

@@ -132,25 +132,27 @@ Bool_t VerifySize(const char *filename, const char *title)
          success = kFALSE;
       else
          success = kTRUE;
-
-      snprintf(gLine,80,"Test %2d: %s", gTestNum, title);
-      const Int_t nch = strlen(gLine);
-      if (success) {
-         std::cout << gLine;
-         for (Int_t i = nch; i < 67; i++) std::cout << ".";
-         std::cout << " OK" << std::endl;
-      } else {
-         std::cout << gLine;
-         for (Int_t i = nch; i < 63; i++) std::cout << ".";
-         std::cout << " FAILED" << std::endl;
-         std::cout << "         File Size = "  << fsize << std::endl;
-         std::cout << "          Ref Size = "  << sizes[gTestNum] << std::endl;
-      }
    } else {
       fprintf(sgref, "%5d%10d\n", gTestNum, fsize);
       success = kTRUE;
    }
-   if (!gOptionKeep && success) gSystem->Unlink(filename);
+
+   snprintf(gLine,80,"Test %2d: %s", gTestNum, title);
+   const Int_t nch = strlen(gLine);
+   if (success) {
+      std::cout << gLine;
+      for (Int_t i = nch; i < 67; i++) std::cout << ".";
+      std::cout << (gOptionRef ? " REF" : " OK") << std::endl;
+   } else {
+      std::cout << gLine;
+      for (Int_t i = nch; i < 63; i++) std::cout << ".";
+      std::cout << " FAILED" << std::endl;
+      std::cout << "         File Size = "  << fsize << std::endl;
+      std::cout << "          Ref Size = "  << sizes[gTestNum] << std::endl;
+   }
+
+   if (!gOptionKeep && success)
+      gSystem->Unlink(filename);
    return success;
 }