minor test fixes

cvxportfolio/data.py

@@ -966,7 +966,7 @@ def _universe_mask_at_time(self, t):
         past_returns = self.returns.loc[self.returns.index < t]
         valid_universe_mask = ((past_returns.count() >= self.min_history) &
             (~self.returns.loc[t].isnull()))
-        if len(sum(valid_universe_mask)) <= 1:
+        if sum(valid_universe_mask) <= 1:
             raise DataError(
                 f'The trading universe at time {t} has size less or equal'
                 + ' than one, i.e., only the cash account. There are probably '

cvxportfolio/tests/test_data.py

@@ -443,14 +443,14 @@ def test_user_provided_market_data(self):
 
         without_prices = UserProvidedMarketData(
             returns=used_returns, volumes=used_prices, cash_key='USDOLLAR',
-            base_location=self.datadir)
+            base_location=self.datadir, min_history=pd.Timedelta('0d'))
         _, _, past_volumes, _,  current_prices = \
             without_prices.serve(t)
         self.assertTrue(current_prices is None)
 
         without_volumes = UserProvidedMarketData(
             returns=used_returns, cash_key='USDOLLAR',
-            base_location=self.datadir)
+            base_location=self.datadir, min_history=pd.Timedelta('0d'))
         _, _, past_volumes, current_volumes, \
             current_prices = without_volumes.serve(t)
 

docs/manual.rst

@@ -213,5 +213,5 @@ Many Cvxportfolio internal variables, such as the weights and holdings vectors
 that you can access in a :class:`cvxportfolio.BacktestResult` object, include
 the cash account as their last element. In most cases used-provided data is not
 concerned with the cash account (such as all examples above) and so it can be
-ignored.
+ignored. Exceptions are noted in the documentation of each object.