unit test for Bcolz writer

tests/exchange/test_bcolz.py

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+import shutil
+import tempfile
+import pandas as pd
+from catalyst.exchange.exchange_bcolz import BcolzExchangeBarWriter
+
+class TestBcolzWriter(object):
+
+	@classmethod
+	def setup_class(cls):
+		cls.columns = ['open', 'high', 'low', 'close', 'volume']
+
+	def setUp(self):
+		# Create a temporary directory
+		self.root_dir = tempfile.mkdtemp()
+
+	def tearDown(self):
+		# Remove the directory after the test
+		shutil.rmtree(self.root_dir)
+
+	def test_bcolz_write_daily(self):
+
+		start = pd.to_datetime('2015-01-01')
+		end   = pd.to_datetime('2015-12-31')
+		freq  = 'daily'
+
+		index = pd.date_range(start=start, end=end, freq='D', name='date')
+		df = pd.DataFrame(index=index, columns=self.columns)
+		df.fillna(1, inplace=True)
+
+		writer = BcolzExchangeBarWriter(
+						rootdir  = self.root_dir,
+						start_session   = start,
+	                    end_session     = end,
+	                    data_frequency  = freq,
+	                    write_metadata  = True )
+
+		data = []
+		data.append((1,df))
+
+		writer.write(data)
+
+
+	def test_bcolz_write_minute(self):
+		index = pd.date_range(start=pd.to_datetime('2015-01-01'), end=pd.to_datetime('2015-01-31'), freq='T', name='date')
+