ENH: Adds a new api_method called get_environment so that users may

check if their algorithm is running in zipline or on Quantopian.

tests/test_algorithm.py

@@ -53,6 +53,7 @@ from zipline.test_algorithms import (
     SetMaxOrderCountAlgorithm,
     SetMaxOrderSizeAlgorithm,
     api_algo,
+    api_get_environment_algo,
     api_symbol_algo,
     call_all_order_methods,
     call_order_in_init,
@@ -407,6 +408,13 @@ class TestAlgoScript(TestCase):
         algo = TradingAlgorithm(script=api_algo)
         algo.run(self.df)
 
+    def test_api_get_environment(self):
+        environment = 'zipline'
+        algo = TradingAlgorithm(script=api_get_environment_algo,
+                                environment=environment)
+        algo.run(self.df)
+        self.assertEqual(algo.environment, environment)
+
     def test_api_symbol(self):
         algo = TradingAlgorithm(script=api_symbol_algo)
         algo.run(self.df)

zipline/algorithm.py

@@ -126,6 +126,8 @@ class TradingAlgorithm(object):
                How much capital to start with.
             instant_fill : bool <default: False>
                Whether to fill orders immediately or on next bar.
+            environment : str <default: 'zipline'>
+               The environment that this algorithm is running in.
         """
         self.datetime = None
 
@@ -139,6 +141,8 @@ class TradingAlgorithm(object):
         self._recorded_vars = {}
         self.namespace = kwargs.get('namespace', {})
 
+        self._environment = kwargs.pop('environment', 'zipline')
+
         self.logger = None
 
         self.benchmark_return_source = None
@@ -470,6 +474,10 @@ class TradingAlgorithm(object):
                                            'args': args,
                                            'kwargs': kwargs}
 
+    @api_method
+    def get_environment(self):
+        return self._environment
+
     @api_method
     def record(self, *args, **kwargs):
         """

zipline/test_algorithms.py

@@ -939,6 +939,16 @@ def handle_data(context, data):
     record(incr=context.incr)
 """
 
+api_get_environment_algo = """
+from zipline.api import get_environment, order, symbol
+
+
+def initialize(context):
+    context.environment = get_environment()
+
+handle_data = lambda context, data: order(symbol(0), 1)
+"""
+
 api_symbol_algo = """
 from zipline.api import (order,
                          symbol)