Re #14022 export weak_ptr to python and move self-assignment test

Framework/API/src/MatrixWorkspace.cpp

@@ -1135,6 +1135,11 @@ MatrixWorkspace::maskedBins(const size_t &workspaceIndex) const {
 */
 void MatrixWorkspace::setMonitorWorkspace(
     const boost::shared_ptr<MatrixWorkspace> &monitorWS) {
+    if (monitorWS.get() == this) {
+      throw std::runtime_error(
+          "To avoid memory leak, monitor workspace"
+          " can not be the same workspace as the host workspace");
+    }
   m_monitorWorkspace = monitorWS;
 }
 

Framework/PythonInterface/mantid/api/src/Exports/MatrixWorkspace.cpp

@@ -89,15 +89,16 @@ void setMonitorWorkspace(MatrixWorkspace &self,
 
   MatrixWorkspace_sptr monWS = boost::dynamic_pointer_cast<MatrixWorkspace>(
       Mantid::PythonInterface::ExtractWorkspace(value)());
-  if (monWS) {
-    if (monWS.get() == &self) {
-      throw std::runtime_error(
-          "To avoid memory leak, monitor workspace"
-          " can not be the same workspace as the host workspace");
-    }
-  }
   self.setMonitorWorkspace(monWS);
 }
+/**
+* @param self  :: A reference to the calling object
+* 
+*@return weak pointer to monitor workspace used by python
+*/
+boost::weak_ptr<MatrixWorkspace> getMonitorWorkspace(MatrixWorkspace &self) {
+	return boost::weak_ptr<MatrixWorkspace>(self.monitorWorkspace());
+}
 /**
  * Clear monitor workspace attached to for current workspace.
  *
@@ -350,7 +351,7 @@ void export_MatrixWorkspace() {
            "Performs a comparison operation on two workspaces, using the "
            "CheckWorkspacesMatch algorithm")
       //---------   monitor workspace --------------------------------------
-      .def("getMonitorWorkspace", &MatrixWorkspace::monitorWorkspace,
+      .def("getMonitorWorkspace", &getMonitorWorkspace,
            args("self"),
            "Return internal monitor workspace bound to current workspace.")
       .def("setMonitorWorkspace", &setMonitorWorkspace,

Framework/PythonInterface/test/python/mantid/api/MatrixWorkspaceTest.py

-import unittest
+import unittest
 import sys
 import math
 from testhelpers import create_algorithm, run_algorithm, can_be_instantiated, WorkspaceCreationHelper
@@ -349,11 +349,11 @@ class MatrixWorkspaceTest(unittest.TestCase):
         run_algorithm('CreateWorkspace', OutputWorkspace='ws1',DataX=[1.,2.,3.], DataY=[2.,3.], DataE=[2.,3.],UnitX='TOF')
         run_algorithm('CreateWorkspace', OutputWorkspace='ws_mon',DataX=[1.,2.,3.], DataY=[2.,3.], DataE=[2.,3.],UnitX='TOF')
         
-        ws1=mtd['ws1']
+        ws1=AnalysisDataService.retrieve('ws1')
         monWs = ws1.getMonitorWorkspace()
         self.assertTrue(monWs is None)
         
-        monWs = mtd['ws_mon']
+        monWs = AnalysisDataService.retrieve('ws_mon')
         ws1.setMonitorWorkspace(monWs)
         monWs.setTitle("My Fake Monitor workspace")
         
@@ -362,13 +362,21 @@ class MatrixWorkspaceTest(unittest.TestCase):
         
         ws1.clearMonitorWorkspace()
         monWs1 = ws1.getMonitorWorkspace()
-        self.assertTrue(monWs1 is None)        
+        self.assertTrue(monWs1 is None)
+
+        # Check weak pointer issues
+        ws1.setMonitorWorkspace(monWs)
+        wms=ws1.getMonitorWorkspace()
+        allFine = False
+        try:
+            ws1.setMonitorWorkspace(wms)
+            allFine = True
+        except ValueError:            
+            pass
+        self.assertTrue(allFine)
 
 if __name__ == '__main__':
-    unittest.main()
+    #unittest.main()
     #Testing particular test from Mantid
-    #class theTester(MatrixWorkspaceTest):
-    #    def runTest():
-    #        pass
-    #tester = theTester()
-    #tester.test_setGetMonitorWS()
+    tester=MatrixWorkspaceTest('test_setGetMonitorWS')
+    tester.test_setGetMonitorWS()