This is a very simple test that calling command('buildinfo') is the same as calling command('buildinfo', 1). The buildinfo command (and various other commands) now return a 'logicalTime' field in MongoDB 3.5, with a value that can change between two consecutive calls.
[2017/03/23 22:02:09.053] ======================================================================
[2017/03/23 22:02:09.053] FAIL: test_command (test_database.TestDatabase)
[2017/03/23 22:02:09.053] ----------------------------------------------------------------------
[2017/03/23 22:02:09.053] Traceback (most recent call last):
[2017/03/23 22:02:09.053] File "/data/mci/715c95a65e803cb37907541c856ed4a2/src/test/test_database.py", line 345, in test_command
[2017/03/23 22:02:09.053] self.assertEqual(db.command("buildinfo"), db.command({"buildinfo": 1}))
[2017/03/23 22:02:09.053] AssertionError: {u'storageEngines': [], u'maxBsonObjectSize': 16777216, u'ok': 1.0, u'bits': 64, [truncated]... != {u'storageEngines': [], u'maxBsonObjectSize': 16777216, u'ok': 1.0, u'bits': 64, [truncated]...
[2017/03/23 22:02:09.053] Diff is 1774 characters long. Set self.maxDiff to None to see it.