Make sure to properly handle signed and unsigned integers that cannot…

… be stored in 64-bits.

hickle/loaders/load_builtins.py

@@ -76,7 +76,7 @@ def create_scalar_dataset(py_obj, h_group, name, **kwargs):
     kwargs.pop('compression', None)
 
     # If py_obj is an integer and cannot be stored in 64-bits, convert to str
-    if isinstance(py_obj, int) and (py_obj.bit_length() > 64):
+    if isinstance(py_obj, int) and not (-2**63 <= py_obj < 2**64):
         py_obj = bytes(str(py_obj), 'ascii')
 
     d = h_group.create_dataset(name, data=py_obj, **kwargs)

hickle/tests/test_hickle.py

@@ -148,11 +148,16 @@ def test_65bit_int():
     """ Dumping and loading an integer with arbitrary precision
 
     https://github.com/telegraphic/hickle/issues/113"""
-    i = 2**65-1
+    i = 2**64
     dump(i, 'test.hdf5')
     i_hkl = load('test.hdf5')
     assert i == i_hkl
 
+    j = -2**63-1
+    dump(j, 'test.hdf5')
+    j_hkl = load('test.hdf5')
+    assert j == j_hkl
+
 
 def test_list():
     """ Dumping and loading a list """