FIX: Check types of args passed to api methods on data

tests/test_algorithm.py

@@ -107,7 +107,22 @@ from zipline.test_algorithms import (
     call_without_kwargs,
     call_with_bad_kwargs_current,
     call_with_bad_kwargs_history,
+    bad_type_history_assets,
+    bad_type_history_fields,
+    bad_type_history_bar_count,
+    bad_type_history_frequency,
+    bad_type_current_assets,
+    bad_type_current_fields,
+    bad_type_can_trade_assets,
+    bad_type_is_stale_assets,
+    bad_type_history_assets_kwarg,
+    bad_type_history_fields_kwarg,
+    bad_type_history_bar_count_kwarg,
+    bad_type_history_frequency_kwarg,
+    bad_type_current_assets_kwarg,
+    bad_type_current_fields_kwarg,
     no_handle_data)
+
 from zipline.testing import (
     make_jagged_equity_info,
     to_utc,
@@ -1431,6 +1446,29 @@ class TestBeforeTradingStart(TestCase):
 
 class TestAlgoScript(TestCase):
 
+    ARG_TYPE_TEST_CASES = [
+        ('history__assets', (bad_type_history_assets, 'Asset, str', True)),
+        ('history__fields', (bad_type_history_fields, 'str', True)),
+        ('history__bar_count', (bad_type_history_bar_count, 'int', False)),
+        ('history__frequency', (bad_type_history_frequency, 'str', False)),
+        ('current__assets', (bad_type_current_assets, 'Asset, str', True)),
+        ('current__fields', (bad_type_current_fields, 'str', True)),
+        ('is_stale__assets', (bad_type_is_stale_assets, 'Asset', True)),
+        ('can_trade__assets', (bad_type_can_trade_assets, 'Asset', True)),
+        ('history_kwarg__assets',
+         (bad_type_history_assets_kwarg, 'Asset, str', True)),
+        ('history_kwarg__fields',
+         (bad_type_history_fields_kwarg, 'str', True)),
+        ('history_kwarg__bar_count',
+         (bad_type_history_bar_count_kwarg, 'int', False)),
+        ('history_kwarg__frequency',
+         (bad_type_history_frequency_kwarg, 'str', False)),
+        ('current_kwarg__assets',
+         (bad_type_current_assets_kwarg, 'Asset, str', True)),
+        ('current_kwarg__fields',
+         (bad_type_current_fields_kwarg, 'str', True)),
+    ]
+
     @classmethod
     def setUpClass(cls):
         setup_logger(cls)
@@ -1846,6 +1884,27 @@ def handle_data(context, data):
         self.assertEqual("%s() got an unexpected keyword argument 'blahblah'"
                          % name, cm.exception.args[0])
 
+    @parameterized.expand(ARG_TYPE_TEST_CASES)
+    def test_arg_types(self, name, inputs):
+
+        keyword = name.split('__')[1]
+
+        with self.assertRaises(TypeError) as cm:
+            algo = TradingAlgorithm(
+                script=inputs[0],
+                sim_params=self.sim_params,
+                env=self.env
+            )
+            algo.run(self.data_portal)
+
+        expected = "Expected %s argument to be of type %s%s" % (
+            keyword,
+            'or iterable of type ' if inputs[2] else '',
+            inputs[1]
+        )
+
+        self.assertEqual(expected, cm.exception.args[0])
+
 
 class TestGetDatetime(TestCase):