Updating support for the DateTime primitive

This change updates the DateTime primitive, adding documentation and
Python string operator support. A new unit test suite for the primitive
is included.

kmip/core/primitives.py

@@ -16,6 +16,7 @@
 import logging
 import six
 import sys
+import time
 
 from struct import pack, unpack
 from enum import Enum
@@ -806,11 +807,37 @@ class ByteString(Base):
 
 
 class DateTime(LongInteger):
+    """
+    An encodeable object representing a date/time value.
+
+    A DateTime is one of the KMIP primitive object types. It is encoded as
+    a signed, big-endian, 64-bit integer, representing a POSIX time value as
+    the number of seconds since the Epoch (1970 January 1, 00:00:00 UTC). For
+    more information, see Section 9.1 of the KMIP 1.1 specification.
+    """
 
     def __init__(self, value=None, tag=Tags.DEFAULT):
+        """
+        Create a DateTime.
+
+        Args:
+            value (int): The value of the DateTime in number of seconds since
+                the Epoch. See the time package for additional information.
+                Optional, defaults to the current time.
+            tag (Tags): An enumeration defining the tag of the LongInteger.
+                Optional, defaults to Tags.DEFAULT.
+        """
+        if value is None:
+            value = int(time.time())
         super(DateTime, self).__init__(value, tag)
         self.type = Types.DATE_TIME
 
+    def __repr__(self):
+        return "DateTime(value={0}, tag={1})".format(self.value, self.tag)
+
+    def __str__(self):
+        return time.ctime(self.value)
+
 
 class Interval(Integer):
 

kmip/tests/unit/core/primitives/test_date_time.py

@@ -14,36 +14,84 @@
 # under the License.
 
 import testtools
+import time
 
+from kmip.core import primitives
 from kmip.core import utils
 
 
 class TestDateTime(testtools.TestCase):
+    """
+    Test suite for the DateTime primitive.
+
+    Since DateTime is a subclass of LongInteger, the bulk of the functionality
+    tests are omitted due to redundancy with the LongInteger test suite.
+    """
 
     def setUp(self):
         super(TestDateTime, self).setUp()
-        self.stream = utils.BytearrayStream()
+
+        self.value = 1335514341
+        self.encoding = (
+            b'\x42\x00\x00\x09\x00\x00\x00\x08\x00\x00\x00\x00\x4F\x9A\x54'
+            b'\xE5')
 
     def tearDown(self):
         super(TestDateTime, self).tearDown()
 
     def test_init(self):
-        self.skip('')
+        """
+        Test that a DateTime can be instantiated.
+        """
+        date_time = primitives.DateTime(1)
+        self.assertEqual(1, date_time.value)
 
     def test_init_unset(self):
-        self.skip('')
-
-    def test_validate_on_valid(self):
-        self.skip('')
-
-    def test_validate_on_valid_unset(self):
-        self.skip('')
-
-    def test_validate_on_invalid_type(self):
-        self.skip('')
+        """
+        Test that a DateTime can be instantiated with no input.
+        """
+        date_time = primitives.DateTime()
+        self.assertNotEqual(date_time.value, None)
 
     def test_read(self):
-        self.skip('')
+        """
+        Test that a DateTime can be read from a byte stream.
+        """
+        stream = utils.BytearrayStream(self.encoding)
+        date_time = primitives.DateTime()
+        date_time.read(stream)
+        self.assertEqual(self.value, date_time.value)
 
     def test_write(self):
-        self.skip('')
+        """
+        Test that a DateTime can be written to a byte stream.
+        """
+        stream = utils.BytearrayStream()
+        date_time = primitives.DateTime(self.value)
+        date_time.write(stream)
+
+        result = stream.read()
+        self.assertEqual(len(self.encoding), len(result))
+        self.assertEqual(self.encoding, result)
+
+    def test_repr(self):
+        """
+        Test that the representation of a DateTime is formatted properly.
+        """
+        date_time = primitives.DateTime(1439299135)
+        value = "value={0}".format(date_time.value)
+        tag = "tag={0}".format(date_time.tag)
+        r = "DateTime({0}, {1})".format(value, tag)
+
+        self.assertEqual(r, repr(date_time))
+
+    def test_str(self):
+        """
+        Test that the string representation of a DateTime is formatted
+        properly.
+        """
+        t = (2015, 8, 11, 9, 18, 55, 1, 223, 1)
+        s = "Tue Aug 11 09:18:55 2015"
+
+        date_time = primitives.DateTime(int(time.mktime(t)))
+        self.assertEqual(s, str(date_time))