[1780] add a replacement time.time() in tests

in the relevant tests, time.time() is temporarily replace by the function returned by get_fake_time_time(). After each test that uses this, it is restored to the original function (So as not to mess up unittest framework's concept of time).

Also renamed one test which had the same name as another test.

src/bin/xfrin/tests/xfrin_test.py

@@ -76,6 +76,27 @@ example_soa_question = Question(TEST_ZONE_NAME, TEST_RRCLASS, RRType.SOA())
 default_questions = [example_axfr_question]
 default_answers = [soa_rrset]
 
+def get_fake_time_time():
+    '''Returns a temporary replacement function for time.time(), which
+       always returns 0.1 more than the previous call. This is to make
+       sure these tests do not fail on systems where the time.time()
+       function has a high minimal accuracy.
+       This fake time.time() is usually set in place of the real one
+       where we need testing of get_running_time(). It is done is
+       as low a scope as possible, so as not to mess up unit test
+       framework time related tests. It must be set before
+       XfrinTransferState (or any class that initializes that) is
+       initialized.
+       And every time it is set up, in must be reset later (again, so
+       as not to mess up the framework's concept of time).
+    '''
+    fake_time = 0.0
+    def fake_time_time():
+        nonlocal fake_time
+        fake_time += 0.1
+        return fake_time
+    return fake_time_time
+
 def check_diffs(assert_fn, expected, actual):
     '''A helper function checking the differences made in the XFR session.
 
@@ -561,7 +582,7 @@ class TestXfrinIXFREnd(TestXfrinState):
     def test_finish_message(self):
         self.assertFalse(self.state.finish_message(self.conn))
 
-class TestXfrinIXFREnd(TestXfrinState):
+class TestXfrinIXFREndUpToDate(TestXfrinState):
     def setUp(self):
         super().setUp()
         self.state = XfrinIXFRUptodate()
@@ -759,9 +780,15 @@ class TestXfrinConnection(unittest.TestCase):
 
 class TestAXFR(TestXfrinConnection):
     def setUp(self):
+        # replace time.time with a steadily increasing fake one
+        self.orig_time_time = time.time
+        time.time = get_fake_time_time()
         super().setUp()
         XfrinInitialSOA().set_xfrstate(self.conn, XfrinInitialSOA())
 
+    def tearDown(self):
+        time.time = self.orig_time_time
+
     def __create_mock_tsig(self, key, error):
         # This helper function creates a MockTSIGContext for a given key
         # and TSIG error to be used as a result of verify (normally faked
@@ -1469,6 +1496,10 @@ class TestAXFR(TestXfrinConnection):
 
 class TestIXFRResponse(TestXfrinConnection):
     def setUp(self):
+        # replace time.time with a steadily increasing fake one
+        self.orig_time_time = time.time
+        time.time = get_fake_time_time()
+
         super().setUp()
         self.conn._query_id = self.conn.qid = 1035
         self.conn._request_serial = isc.dns.Serial(1230)
@@ -1476,6 +1507,9 @@ class TestIXFRResponse(TestXfrinConnection):
         self.conn._datasrc_client = MockDataSourceClient()
         XfrinInitialSOA().set_xfrstate(self.conn, XfrinInitialSOA())
 
+    def tearDown(self):
+        time.time = self.orig_time_time
+
     def test_ixfr_response(self):
         '''A simplest form of IXFR response.
 
@@ -1670,8 +1704,14 @@ class TestIXFRSession(TestXfrinConnection):
     the general logic flow.
     '''
     def setUp(self):
+        # replace time.time with a steadily increasing fake one
+        self.orig_time_time = time.time
+        time.time = get_fake_time_time()
         super().setUp()
 
+    def tearDown(self):
+        time.time = self.orig_time_time
+
     def test_do_xfrin(self):
         def create_ixfr_response():
             self.conn.reply_data = self.conn.create_response_data(
@@ -1758,6 +1798,9 @@ class TestXFRSessionWithSQLite3(TestXfrinConnection):
         self.empty_sqlite3db_obj = TESTDATA_OBJDIR + '/empty.sqlite3'
         self.sqlite3db_cfg = "{ \"database_file\": \"" +\
                              self.sqlite3db_obj + "\"}"
+        # replace time.time with a steadily increasing fake one
+        self.orig_time_time = time.time
+        time.time = get_fake_time_time()
         super().setUp()
         if os.path.exists(self.sqlite3db_obj):
             os.unlink(self.sqlite3db_obj)
@@ -1772,6 +1815,7 @@ class TestXFRSessionWithSQLite3(TestXfrinConnection):
             os.unlink(self.sqlite3db_obj)
         if os.path.exists(self.empty_sqlite3db_obj):
             os.unlink(self.empty_sqlite3db_obj)
+        time.time = self.orig_time_time
 
     def get_zone_serial(self):
         result, finder = self.conn._datasrc_client.find_zone(TEST_ZONE_NAME)
@@ -2741,8 +2785,14 @@ class TestFormatting(unittest.TestCase):
 
 class TestXfrinTransferStats(unittest.TestCase):
     def setUp(self):
+        # replace time.time with a steadily increasing fake one
+        self.orig_time_time = time.time
+        time.time = get_fake_time_time()
         self.stats = XfrinTransferStats()
 
+    def tearDown(self):
+        time.time = self.orig_time_time
+
     def zero_check(self):
         # Checks whether all counters are zero
         self.assertEqual(0, self.stats.message_count)
@@ -2795,7 +2845,6 @@ class TestXfrinTransferStats(unittest.TestCase):
         zbps = self.stats.get_bytes_per_second()
         self.assertEqual(0, zbps)
 
-
 if __name__== "__main__":
     try:
         isc.log.resetUnitTestRootLogger()