Fix #154 . Add copy/deepcopy methods for DataChunk and add tests (#155)

src/hdmf/data_utils.py

@@ -397,6 +397,17 @@ def __getattr__(self, attr):
         """Delegate retrival of attributes to the data in self.data"""
         return getattr(self.data, attr)
 
+    def __copy__(self):
+        newobj = DataChunk(data=self.data,
+                           selection=self.selection)
+        return newobj
+
+    def __deepcopy__(self, memo):
+        result = DataChunk(data=copy.deepcopy(self.data),
+                           selection=copy.deepcopy(self.selection))
+        memo[id(self)] = result
+        return result
+
     def astype(self, dtype):
         """Get a new DataChunk with the self.data converted to the given type"""
         return DataChunk(data=self.data.astype(dtype),

tests/unit/utils_test/test_core_DataChunk.py

@@ -0,0 +1,39 @@
+import unittest2 as unittest
+
+from hdmf.data_utils import DataChunk
+import numpy as np
+from copy import copy, deepcopy
+
+
+class DataChunkTests(unittest.TestCase):
+
+    def setUp(self):
+        pass
+
+    def tearDown(self):
+        pass
+
+    def test_datachunk_copy(self):
+        obj = DataChunk(data=np.arange(3), selection=np.s_[0:3])
+        obj_copy = copy(obj)
+        self.assertNotEqual(id(obj), id(obj_copy))
+        self.assertEqual(id(obj.data), id(obj_copy.data))
+        self.assertEqual(id(obj.selection), id(obj_copy.selection))
+
+    def test_datachunk_deepcopy(self):
+        obj = DataChunk(data=np.arange(3), selection=np.s_[0:3])
+        obj_copy = deepcopy(obj)
+        self.assertNotEqual(id(obj), id(obj_copy))
+        self.assertNotEqual(id(obj.data), id(obj_copy.data))
+        self.assertNotEqual(id(obj.selection), id(obj_copy.selection))
+
+    def test_datachunk_astype(self):
+        obj = DataChunk(data=np.arange(3), selection=np.s_[0:3])
+        newtype = np.dtype('int16')
+        obj_astype = obj.astype(newtype)
+        self.assertNotEqual(id(obj), id(obj_astype))
+        self.assertEqual(obj_astype.dtype, np.dtype(newtype))
+
+
+if __name__ == '__main__':
+    unittest.main()