fixes #45

CHANGES.rst

@@ -7,6 +7,8 @@ Change History
 Production
 **********
 
+:2016.0204.0: handle case when no data points in scan (`issue #45 <https://github.com/prjemian/spec2nexus/issues/45>`_), 
+              spec.getScan() ensures argument is used as ``str`` (`issue #46 <https://github.com/prjemian/spec2nexus/issues/46>`_)
 :2016.0201.0: added spec.getScanNumbersChronological(), spec.getFirstScanNumber(), and spec.getLastScanNumber()
 :2016.0131.0: support new NeXus method for default/signal/axes/_indices, 
               `issue #43 <https://github.com/prjemian/spec2nexus/issues/43>`_

src/spec2nexus/dev_nexus.py

@@ -0,0 +1,24 @@
+#!/usr/bin/env python 
+# -*- coding: utf-8 -*-
+
+'''developer test for nexus'''
+
+#-----------------------------------------------------------------------------
+# :author:    Pete R. Jemian
+# :email:     prjemian@gmail.com
+# :copyright: (c) 2014-2016, Pete R. Jemian
+#
+# Distributed under the terms of the Creative Commons Attribution 4.0 International Public License.
+#
+# The full license is in the file LICENSE.txt, distributed with this software.
+#-----------------------------------------------------------------------------
+
+
+import sys
+import nexus
+
+args = 'data/02_03_setup.dat  -f --verbose   -s 46'
+for _ in args.split():
+    sys.argv.append(_)
+
+nexus.main()

src/spec2nexus/writer.py

@@ -81,6 +81,26 @@ def save(self, hdf_file, scan_list=[]):
             if pick_first_entry:
                 pick_first_entry = False
                 eznx.addAttributes(root, default='S'+str(key))
+            if 'data' not in nxentry:
+                # resolve issue #45 here
+                # NXentry MUST have a NXdata group with data for default plot
+                nxdata = eznx.makeGroup(nxentry, 
+                                        'data', 
+                                        'NXdata',
+                                        signal='no_y_data',
+                                        axes='no_x_data',
+                                        no_x_data_indices=[0,],
+                                        )
+                eznx.makeDataset(nxdata, 
+                                 "no_x_data", 
+                                 (0, 1), 
+                                 units='none',
+                                 long_name='no data points in this scan')
+                eznx.makeDataset(nxdata, 
+                                 "no_y_data", 
+                                 (0, 1), 
+                                 units='none',
+                                 long_name='no data points in this scan')
         root.close()    # be CERTAIN to close the file
 
     def root_attributes(self):