Issue246 (#267)

* recreate cdms2 with libpng from conda-forge

* force libpng=1.6.34 in circleci yml

* fix #246 clone axis units issue

* add test

Lib/axis.py

@@ -1708,13 +1708,13 @@ def clone(self, copyData=1):
         else:
             mycopy = createAxis(self[:])
         mycopy.id = self.id
+        mycopy.__dict__.update(self.__dict__.copy())
+        mycopy._obj_ = None  # Erase Cdfile object if exist
         try:
             mycopy.setBounds(b, isGeneric=isGeneric[0])
         except CDMSError:
             b = mycopy.genGenericBounds()
             mycopy.setBounds(b, isGeneric=False)
-        for k, v in list(self.attributes.items()):
-            setattr(mycopy, k, v)
         return mycopy
 
     def listall(self, all=None):

tests/test_cdms_axis_clone.py

@@ -0,0 +1,28 @@
+from __future__ import print_function
+import unittest
+import os
+from subprocess import Popen, PIPE
+import shlex
+import MV2, cdms2
+
+
+class TestAxis(unittest.TestCase):
+
+    def testCloneUnits(self):
+
+        tmp = MV2.ones(3, id='tmp')
+        ax = tmp.getAxis(0)
+        ax.standard_name = "time"
+        ax.id = 'time'
+        ax.units = "seconds since 1900-01-01T00:00:00Z"
+        ax.long_name = "time in seconds (UT)"
+        ax.time_origin = "01-JAN-1900 00:00:00"
+        ax.designateTime()
+
+        f = cdms2.open('tmp.nc', 'w')
+        f.write(tmp)
+        f.close()
+
+        f = cdms2.open('tmp.nc') 
+        assert f['time'].clone().units == f['time'].units
+        f.close()