TST: Changed the error raised by no tables in data.io.Options

Tests were failing if the scraper got the webpage but there weren't any tables in it. Added condition to raise RemoteDataError if no tables were found.  Still IndexError if it can't find the correct table.

Author: davidastephens

pandas/io/data.py

@@ -664,7 +664,9 @@ def _get_option_data(self, month, year, expiry, table_loc, name):
                                       "element".format(url))
             tables = root.xpath('.//table')
             ntables = len(tables)
-            if table_loc - 1 > ntables:
+            if ntables == 0:
+                raise RemoteDataError("No tables found at {0!r}".format(url))
+            elif table_loc - 1 > ntables:
                 raise IndexError("Table location {0} invalid, {1} tables"
                                  " found".format(table_loc, ntables))