fix: resolve linting issues (ruff)

- Fix import sorting

- Remove trailing whitespace

- Fix boolean comparison

- Rename unused variable

- Add trailing newline

Author: saumya1317

.coverage

@@ -1,9 +1,11 @@
 """Vectorized backtesting engine."""
 
 from typing import Dict, Optional
+
 import numpy as np
 import pandas as pd
 
+
 class VectorizedBacktest:
     """
     Vectorized backtester for quantitative strategies.
@@ -22,7 +24,7 @@ def __init__(
         initial_capital: float = 1_000_000,
         transaction_cost: float = 0.001,  # 10 bps
         max_leverage: float = 1.0,
-        min_position_size: float = 0.001,  
+        min_position_size: float = 0.001,
         rebalance_freq: str = "D",
     ):
         """
@@ -90,8 +92,8 @@ def run(self, weight_scheme: str = "rank") -> Dict:
         rebalance_mask = weights.index.map(self._should_rebalance)
         # Broadcast mask to match DataFrame shape
         rebalance_mask_df = pd.DataFrame(
-            np.tile(rebalance_mask.values.reshape(-1, 1), (1, len(weights.columns))), 
-            index=weights.index, 
+            np.tile(rebalance_mask.values.reshape(-1, 1), (1, len(weights.columns))),
+            index=weights.index,
             columns=weights.columns
         )
         weights = weights.where(rebalance_mask_df, weights.shift(1).fillna(0.0))

src/quant_research_starter/backtest/__pycache__/vectorized.cpython-313.pyc

@@ -155,11 +155,11 @@ def test_should_rebalance_logic(self):
         # Test daily rebalancing
         backtest_daily = VectorizedBacktest(prices, signals, rebalance_freq="D")
         for date in dates:
-            assert backtest_daily._should_rebalance(date) == True
+            assert backtest_daily._should_rebalance(date)
 
         # Test weekly rebalancing (should rebalance on Mondays)
         backtest_weekly = VectorizedBacktest(prices, signals, rebalance_freq="W")
-        for i, date in enumerate(dates):
+        for _i, date in enumerate(dates):
             expected = date.weekday() == 0  # Monday
             assert backtest_weekly._should_rebalance(date) == expected
 
@@ -172,7 +172,7 @@ def test_should_rebalance_logic(self):
     def test_invalid_rebalance_frequency(self, sample_data):
         """Test that invalid rebalance frequency raises error."""
         prices, signals = sample_data
-        
+
         with pytest.raises(ValueError, match="Unsupported rebalance frequency"):
             backtest = VectorizedBacktest(prices, signals, rebalance_freq="X")
             backtest.run()
@@ -209,4 +209,4 @@ def test_rebalancing_frequency_impact(self, sample_data):
 
         # Weekly and monthly should have fewer position changes than daily
         assert weekly_changes <= daily_changes
-        assert monthly_changes <= daily_changes
+        assert monthly_changes <= daily_changes