TST: Remove asset finder test for NASDAQ collisions.

The asset finder retrieved from the test environment is empty, so the
test does not end up testing anything, since the test cases loop over
the empty list of sids in the asset finder.

Remove to possibly be added back in and re-implemented after a larger
refactoring of the module.

tests/test_assets.py

@@ -25,14 +25,12 @@ from datetime import (
     datetime
 )
 import pickle
-import pprint
 import uuid
 import warnings
 import pandas as pd
 
 from nose_parameterized import parameterized
 
-from zipline.finance.trading import with_environment
 from zipline.assets import Asset, Equity, Future, AssetFinder
 from zipline.errors import (
     SymbolNotFound,
@@ -355,43 +353,6 @@ class AssetFinderTestCase(TestCase):
                 self.assertEqual(result.symbol, 'existing')
                 self.assertEqual(result.sid, i)
 
-    @with_environment()
-    def test_lookup_symbol_nasdaq_underscore_collisions(self, env=None):
-        """
-        Ensure that each NASDAQ symbol without underscores maps back to the
-        original symbol when using fuzzy matching.
-        """
-        sf = env.asset_finder
-        fuzzy_str = '_'
-        collisions = []
-
-        try:
-            for sid in sf.sids:
-                sec = sf.retrieve_asset(sid)
-                if sec.exchange.startswith('NASDAQ'):
-                    found = sf.lookup_symbol(sec.symbol.replace(fuzzy_str, ''),
-                                             sec.end_date, fuzzy=fuzzy_str)
-                    if found != sec:
-                        collisions.append((found, sec))
-
-            # KNOWN BUG: Filter out assets that have intersections in their
-            # start and end dates.  We can't correctly resolve these.
-            unexpected_errors = []
-            for first, second in collisions:
-                overlapping_dates = (
-                    first.end_date >= second.start_date or
-                    second.end_date >= first.end_date
-                )
-                if not overlapping_dates:
-                    unexpected_errors.append((first, second))
-
-            self.assertFalse(
-                unexpected_errors,
-                pprint.pformat(unexpected_errors),
-            )
-        finally:
-            env.update_asset_finder(clear_metadata=True)
-
     @parameterized.expand(
         build_lookup_generic_cases()
     )