'Test writing multiple sids.
Tests both that the data is written to the correct sid, as well as
ensuring that the logic for creating the subdirectory path to each sid
does not cause issues from attempts to recreate existing paths.
(Calling out this coverage, because an assertion of that logic does not
show up in the test itself, but is exercised by the act of attempting
to write two consecutive sids, which would be written to the same
containing directory, `00/00/000001.bcolz` and `00/00/000002.bcolz)
Before applying a check to make sure the path writing did not
re-attempt directory creation an OSError like the following would
occur:
OSError: [Errno 17] File exists: \'/tmp/tmpR7yzzT/minute_bars/00/00\''

def test_write_multiple_sids(self):

    minute = self.market_opens[TEST_CALENDAR_START]
    sids = [1, 2]
    data = DataFrame(data={'open': [15.0], 'high': [17.0], 'low': [11.0], 'close': [15.0], 'volume': [100.0]}, index=[minute])
    self.writer.write_sid(sids[0], data)
    data = DataFrame(data={'open': [25.0], 'high': [27.0], 'low': [21.0], 'close': [25.0], 'volume': [200.0]}, index=[minute])
    self.writer.write_sid(sids[1], data)
    sid = sids[0]
    open_price = self.reader.get_value(sid, minute, 'open')
    self.assertEquals(15.0, open_price)
    high_price = self.reader.get_value(sid, minute, 'high')
    self.assertEquals(17.0, high_price)
    low_price = self.reader.get_value(sid, minute, 'low')
    self.assertEquals(11.0, low_price)
    close_price = self.reader.get_value(sid, minute, 'close')
    self.assertEquals(15.0, close_price)
    volume_price = self.reader.get_value(sid, minute, 'volume')
    self.assertEquals(100.0, volume_price)
    sid = sids[1]
    open_price = self.reader.get_value(sid, minute, 'open')
    self.assertEquals(25.0, open_price)
    high_price = self.reader.get_value(sid, minute, 'high')
    self.assertEquals(27.0, high_price)
    low_price = self.reader.get_value(sid, minute, 'low')
    self.assertEquals(21.0, low_price)
    close_price = self.reader.get_value(sid, minute, 'close')
    self.assertEquals(25.0, close_price)
    volume_price = self.reader.get_value(sid, minute, 'volume')
    self.assertEquals(200.0, volume_price)
