Re #12687 clone() for MementoTableWorkspace.

Previously (before 12687) there was no implementation of clone(). That
is, when calling clone() though a base class (e.g., ITableWorkspace) we
would use TableWorkspace::clone() on an object of type
MementoTableWorkspace. Was that doing the right thing?

Code/Mantid/Framework/DataObjects/inc/MantidDataObjects/MementoTableWorkspace.h

@@ -40,13 +40,23 @@ class DLLExport MementoTableWorkspace : public TableWorkspace {
   MementoTableWorkspace(int nRows = 0);
   ~MementoTableWorkspace();
 
+  /// Returns a clone of the workspace
+  std::unique_ptr<MementoTableWorkspace> clone() const {
+    return std::unique_ptr<MementoTableWorkspace>(doClone());
+  }
+
 protected:
   /// Protected copy constructor. May be used by childs for cloning.
-  MementoTableWorkspace(const MementoTableWorkspace &other);
+  MementoTableWorkspace(const MementoTableWorkspace &other)
+      : ITableWorkspace(other), TableWorkspace(other) {}
   /// Protected copy assignment operator. Assignment not implemented.
   MementoTableWorkspace &operator=(const MementoTableWorkspace &other);
 
 private:
+  virtual MementoTableWorkspace *doClone() const {
+    return new MementoTableWorkspace(*this);
+  }
+
   static bool expectedColumn(Mantid::API::Column_const_sptr expected,
                              Mantid::API::Column_const_sptr candidate);
 };

Code/Mantid/Framework/DataObjects/test/MementoTableWorkspaceTest.h

@@ -29,6 +29,40 @@ class MementoTableWorkspaceTest : public CxxTest::TestSuite
     TSM_ASSERT_EQUALS("Wrong number of columns constructed", 11, pWs->columnCount());
   }
 
+  void testClone()
+  {
+    MementoTableWorkspace tw(1);
+
+    tw.getColumn(0)->cell<std::string>(0) = "a";
+    tw.getColumn(1)->cell<std::string>(0) = "b";
+    tw.getColumn(2)->cell<int>(0) = 421;
+    tw.getColumn(3)->cell<std::string>(0) = "c";
+    tw.getColumn(4)->cell<double>(0) = 1.1;
+    tw.getColumn(5)->cell<double>(0) = 2.1;
+    tw.getColumn(6)->cell<double>(0) = 3.1;
+    tw.getColumn(7)->cell<double>(0) = 4.1;
+    tw.getColumn(8)->cell<double>(0) = 5.1;
+    tw.getColumn(9)->cell<double>(0) = 6.1;
+    tw.getColumn(10)->cell<std::string>(0) = "d";
+
+    auto cloned = tw.clone();
+
+    // Check clone is same as original.
+    TS_ASSERT_EQUALS(tw.columnCount(), cloned->columnCount());
+    TS_ASSERT_EQUALS(tw.rowCount(), cloned->rowCount());
+    TS_ASSERT_EQUALS("a", cloned->getColumn(0)->cell<std::string>(0));
+    TS_ASSERT_EQUALS("b", cloned->getColumn(1)->cell<std::string>(0));
+    TS_ASSERT_EQUALS(421, cloned->getColumn(2)->cell<int>(0));
+    TS_ASSERT_EQUALS("c", cloned->getColumn(3)->cell<std::string>(0));
+    TS_ASSERT_EQUALS(1.1, cloned->getColumn(4)->cell<double>(0));
+    TS_ASSERT_EQUALS(2.1, cloned->getColumn(5)->cell<double>(0));
+    TS_ASSERT_EQUALS(3.1, cloned->getColumn(6)->cell<double>(0));
+    TS_ASSERT_EQUALS(4.1, cloned->getColumn(7)->cell<double>(0));
+    TS_ASSERT_EQUALS(5.1, cloned->getColumn(8)->cell<double>(0));
+    TS_ASSERT_EQUALS(6.1, cloned->getColumn(9)->cell<double>(0));
+    TS_ASSERT_EQUALS("d", cloned->getColumn(10)->cell<std::string>(0));
+  }
+
   void testCompareWithWrongNColumns()
   {
     //Create a table workspace with too few columns.