Fix vertical axis creation

WorkspaceCreation was failing to create a properly sized BinEdgeAxis
from a parent workspace.

Re #24355

Framework/API/src/WorkspaceFactory.cpp

@@ -5,6 +5,7 @@
 //     & Institut Laue - Langevin
 // SPDX - License - Identifier: GPL - 3.0 +
 #include "MantidAPI/WorkspaceFactory.h"
+#include "MantidAPI/BinEdgeAxis.h"
 #include "MantidAPI/IPeaksWorkspace.h"
 #include "MantidAPI/ITableWorkspace.h"
 #include "MantidAPI/MatrixWorkspace.h"
@@ -127,10 +128,12 @@ void WorkspaceFactoryImpl::initializeFromParent(
 
   // deal with axis
   for (size_t i = 0; i < parent.m_axes.size(); ++i) {
-    const size_t newAxisLength = child.getAxis(i)->length();
-    const size_t oldAxisLength = parent.getAxis(i)->length();
+    const bool isBinEdge =
+        dynamic_cast<const BinEdgeAxis *const>(parent.m_axes[i]) != nullptr;
+    const size_t newAxisLength = child.m_axes[i]->length() + (isBinEdge ? 1 : 0);
+    const size_t oldAxisLength = parent.m_axes[i]->length();
 
-    if (!differentSize || newAxisLength == oldAxisLength) {
+    if (!differentSize && newAxisLength == oldAxisLength) {
       // Need to delete the existing axis created in init above
       delete child.m_axes[i];
       // Now set to a copy of the parent workspace's axis

Framework/DataObjects/test/WorkspaceCreationTest.h

@@ -9,6 +9,7 @@
 
 #include <cxxtest/TestSuite.h>
 
+#include "MantidAPI/BinEdgeAxis.h"
 #include "MantidAPI/Run.h"
 #include "MantidDataObjects/EventWorkspace.h"
 #include "MantidDataObjects/SpecialWorkspace2D.h"
@@ -419,6 +420,30 @@ public:
     check_zeroed_data(*ws);
   }
 
+  void test_create_parent_numeric_vertical_axis() {
+    constexpr size_t parentNhist{3};
+    const auto parent = create<Workspace2D>(parentNhist, Histogram(Points{1}));
+    NumericAxis *parentAxis = new NumericAxis({-1.5, -0.5, 2.3});
+    parent->replaceAxis(1, parentAxis);
+    constexpr size_t nhist{2};
+    const auto ws = create<Workspace2D>(*parent, nhist, parent->histogram(0));
+    auto axis = ws->getAxis(1);
+    TS_ASSERT_DIFFERS(dynamic_cast<NumericAxis *>(axis), nullptr)
+    TS_ASSERT_EQUALS(axis->length(), nhist);
+  }
+
+  void test_create_parent_bin_edge_vertical_axis() {
+    constexpr size_t parentNhist{3};
+    const auto parent = create<Workspace2D>(parentNhist, Histogram(Points{1}));
+    BinEdgeAxis *parentAxis = new BinEdgeAxis({-1.5, -0.5, 2.3, 3.4});
+    parent->replaceAxis(1, parentAxis);
+    constexpr size_t nhist{2};
+    const auto ws = create<Workspace2D>(*parent, nhist, parent->histogram(0));
+    auto axis = ws->getAxis(1);
+    TS_ASSERT_DIFFERS(dynamic_cast<BinEdgeAxis *>(axis), nullptr)
+    TS_ASSERT_EQUALS(axis->length(), nhist + 1);
+  }
+
   void test_create_drop_events() {
     auto eventWS = create<EventWorkspace>(1, Histogram(BinEdges(3)));
     auto ws = create<HistoWorkspace>(*eventWS);