ENH: Adds Security cython class in new package 'zipline.assets'

The class is not yet used. Adding this class is part of the effort to allow Zipline
simulation of more types of assets than stocks.

DEV: Adds build_ext to .travis.yml

tests/test_assets.py

@@ -0,0 +1,49 @@
+#
+# Copyright 2015 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.
+
+"""
+Tests for the zipline.assets package
+"""
+
+from unittest import TestCase
+
+from zipline.assets._securities import Security
+
+
+class SecurityTestCase(TestCase):
+
+    def test_security_object(self):
+        self.assertEquals({5061: 'foo'}[Security(5061)], 'foo')
+        self.assertEquals(Security(5061), 5061)
+        self.assertEquals(5061, Security(5061))
+
+        self.assertEquals(Security(5061), Security(5061))
+        self.assertEquals(int(Security(5061)), 5061)
+
+        self.assertEquals(str(Security(5061)), 'Security(5061)')
+
+        # TODO: we can't provide this property while subclassing
+        # int. Need to subclass object to fix all the following
+        # cases.
+        # assert Security(5061) != 5061.0
+
+        # with self.assertRaises(TypeError):
+        #    assert Security(5061) + Security(5061)
+
+        # with self.assertRaises(TypeError):
+        #    print float(Security(5061))
+
+        # with self.assertRaises(TypeError):
+        #    print float(Security(5061))