Implementing _convert_to_time_range helper.

This is to help convert millisecond timestamps into the "next"
TimestampRange (as a compatibility between HBase and Cloud Bigtable).

gcloud_bigtable/happybase/table.py

@@ -17,10 +17,12 @@
 
 import struct
 
+from gcloud_bigtable._helpers import _microseconds_to_timestamp
 from gcloud_bigtable.column_family import GarbageCollectionRule
 from gcloud_bigtable.column_family import GarbageCollectionRuleIntersection
 from gcloud_bigtable.happybase.batch import Batch
 from gcloud_bigtable.happybase.batch import _WAL_SENTINEL
+from gcloud_bigtable.row import TimestampRange
 from gcloud_bigtable.table import Table as _LowLevelTable
 
 
@@ -125,6 +127,29 @@ def _gc_rule_to_dict(gc_rule):
     return result
 
 
+def _convert_to_time_range(timestamp=None):
+    """Create a timestamp range from an HBase / HappyBase timestamp.
+
+    HBase uses timestamp as an argument to specify an inclusive end
+    deadline. Since Cloud Bigtable uses exclusive end times, we increment
+    by one millisecond (the lowest granularity allowed).
+
+    :type timestamp: int
+    :param timestamp: (Optional) Timestamp (in milliseconds since the
+                      epoch). Intended to be used as the end of an HBase
+                      time range, which is inclusive.
+
+    :rtype: :class:`.TimestampRange`, :data:`NoneType <types.NoneType>`
+    :returns: The timestamp range corresponding to the passed in
+              ``timestamp``.
+    """
+    if timestamp is None:
+        return None
+
+    next_timestamp = _microseconds_to_timestamp(1000 * (timestamp + 1))
+    return TimestampRange(end=next_timestamp)
+
+
 class Table(object):
     """Representation of Cloud Bigtable table.
 

gcloud_bigtable/happybase/test_table.py

@@ -130,6 +130,34 @@ def test_with_intersection_two_nested_rules(self):
         self.assertTrue(result is gc_rule)
 
 
+class Test__convert_to_time_range(unittest2.TestCase):
+
+    def _callFUT(self, timestamp=None):
+        from gcloud_bigtable.happybase.table import _convert_to_time_range
+        return _convert_to_time_range(timestamp=timestamp)
+
+    def test_null(self):
+        timestamp = None
+        result = self._callFUT(timestamp=timestamp)
+        self.assertEqual(result, None)
+
+    def test_invalid_type(self):
+        timestamp = object()
+        with self.assertRaises(TypeError):
+            self._callFUT(timestamp=timestamp)
+
+    def test_success(self):
+        from gcloud_bigtable._helpers import _microseconds_to_timestamp
+        from gcloud_bigtable.row import TimestampRange
+
+        timestamp = 1441928298571
+        next_ts = _microseconds_to_timestamp(1000 * (timestamp + 1))
+        result = self._callFUT(timestamp=timestamp)
+        self.assertTrue(isinstance(result, TimestampRange))
+        self.assertEqual(result.start, None)
+        self.assertEqual(result.end, next_ts)
+
+
 class TestTable(unittest2.TestCase):
 
     def _getTargetClass(self):