BUG: ensure perf stats are generated for all days

When running with minutely emissions the simulator would report to the
user that it simulated 'n - 1' days (where n is the number of days
specified in the simulation params).  Now the correct number of trading
days are reported as being simulated.

tests/test_tradesimulation.py

@@ -0,0 +1,28 @@
+#
+# Copyright 2014 Quantopian, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from unittest import TestCase
+from zipline.test_algorithms import NoopAlgorithm
+from zipline.utils import factory
+
+
+class TestTradeSimulation(TestCase):
+
+    def test_minutely_emissions_generate_performance_stats_for_last_day(self):
+        params = factory.create_simulation_parameters(num_days=1)
+        params.emission_rate = 'minute'
+        algo = NoopAlgorithm()
+        algo.run(source=[], sim_params=params)
+        self.assertEqual(algo.perf_tracker.day_count, 1.0)