add test to capture PlanWidget behavior overwriting the isocenter in the workspace with nan if multiple isocenters are defined

Author: wahln

test/gui/test_gui_PlanWidget.m

@@ -110,5 +110,34 @@
     evalin('base','clear ct cst pln stf dij resultGUI');
     delete(h);
 
+function test_PlanWidget_multiisocenter
+    evalin('base','load protons_testData.mat');
+    
+    %Modify to have multiple isocenters
+    pln = evalin('base','pln');
+    pln.propStf.isoCenter(2,:) = [0 0 0];
+    iso = pln.propStf.isoCenter;
+    assignin('base','pln',pln);
+
+    h = matRad_PlanWidget();
+
+    % check correct value in isocenter edit field
+    str = get(h.handles.editIsoCenter,'String');
+    assertEqual(str,'multiple isoCenter'); 
+
+    %Now force an update by changing a value and executing the callback
+    set(h.handles.editBixelWidth,'String','1');
+    cb = get(h.handles.editBixelWidth,'Callback');
+    cb(h.handles.editBixelWidth,[]);
+    
+    str = get(h.handles.editIsoCenter,'String');
+    assertEqual(str,'multiple isoCenter'); 
+    pln = evalin('base','pln');        
+    assertEqual(pln.propStf.isoCenter,iso);
+
+    evalin('base','clear ct cst pln stf dij resultGUI');
+    delete(h);
+
+
 
 %TODO: Test Buttons