Add new business helpers

src/business_tools.py

@@ -21,3 +21,45 @@ def get_sales_from_csv(filename: str) -> float:
 def calculate_commission(premiums: list[float], rate: float = 0.1) -> float:
     """Return total commission in USD rounded to two decimals."""
     return round(sum(premiums) * rate, 2)
+
+
+def load_insurance_sales(filename: str) -> list[dict[str, str]]:
+    """Return all rows from an insurance sales CSV as dictionaries.
+
+    Args:
+        filename: Path to ``insurance_sales.csv``.
+
+    Returns:
+        A list of dictionaries, one per CSV row.
+    """
+    with open(filename, newline="") as csvfile:
+        reader = csv.DictReader(csvfile)
+        return list(reader)
+
+
+def total_commission(records: list[dict[str, str]]) -> float:
+    """Return the sum of the ``Commission`` column from insurance records.
+
+    Args:
+        records: Rows loaded via :func:`load_insurance_sales`.
+
+    Returns:
+        Total commission as a float.
+    """
+    total = 0.0
+    for row in records:
+        total += float(row["Commission"])
+    return total
+
+
+def filter_by_state(records: list[dict[str, str]], state: str) -> list[dict[str, str]]:
+    """Return only the rows matching a given state code.
+
+    Args:
+        records: Insurance sale rows.
+        state: Two-letter state abbreviation.
+
+    Returns:
+        Filtered list containing rows where ``State`` equals ``state``.
+    """
+    return [row for row in records if row["State"] == state]

tests/test_business_tools.py

@@ -1,13 +1,19 @@
 
 import os
 import sys
-import pytest
 
 # Ensure the repository root is on sys.path so business_tools can be imported
 REPO_ROOT = os.path.abspath(os.path.join(os.path.dirname(__file__), os.pardir))
 sys.path.insert(0, os.path.join(REPO_ROOT, "src"))
 
-from business_tools import calculate_profit, get_sales_from_csv, calculate_commission
+from business_tools import (  # noqa: E402
+    calculate_profit,
+    get_sales_from_csv,
+    calculate_commission,
+    load_insurance_sales,
+    total_commission,
+    filter_by_state,
+)
 
 
 def test_calculate_profit():
@@ -26,3 +32,23 @@ def test_get_sales_from_csv(tmp_path):
 def test_calculate_commission():
     premiums = [300, 700, 200]
     assert calculate_commission(premiums, rate=0.1) == 120.0
+
+
+def test_load_insurance_sales_and_total_commission(tmp_path):
+    src = os.path.join(REPO_ROOT, "data", "insurance_sales.csv")
+    dst = tmp_path / "insurance_sales.csv"
+    with open(src, "r") as fsrc, open(dst, "w") as fdst:
+        fdst.write(fsrc.read())
+    records = load_insurance_sales(str(dst))
+    assert len(records) == 15
+    assert total_commission(records) == 2545.0
+
+
+def test_filter_by_state(tmp_path):
+    src = os.path.join(REPO_ROOT, "data", "insurance_sales.csv")
+    dst = tmp_path / "insurance_sales.csv"
+    with open(src, "r") as fsrc, open(dst, "w") as fdst:
+        fdst.write(fsrc.read())
+    records = load_insurance_sales(str(dst))
+    ca_records = filter_by_state(records, "CA")
+    assert len(ca_records) == 4