feat: cross-account transfer detection

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
2026-02-10 14:56:53 -05:00
parent a3fae3fa95
commit f538cad6ae
2 changed files with 184 additions and 0 deletions
--- a/tests/services/test_transfer_detector.py
+++ b/tests/services/test_transfer_detector.py
@@ -0,0 +1,99 @@
+import datetime
+from sqlalchemy import create_engine
+from sqlalchemy.orm import Session
+
+from src.db import Base
+from src.models import *
+from src.services.transfer_detector import TransferDetector
+
+
+def make_session():
+    engine = create_engine("sqlite:///:memory:")
+    Base.metadata.create_all(engine)
+    return Session(engine)
+
+
+def test_detect_matching_transfer():
+    session = make_session()
+    member = HouseholdMember(name="Andrew", relationship="self")
+    session.add(member)
+    session.flush()
+    checking = Account(name="Checking", institution="WF", account_type="checking", owner_id=member.id)
+    chase = Account(name="Chase", institution="Chase", account_type="credit", owner_id=member.id)
+    session.add_all([checking, chase])
+    session.flush()
+
+    # Payment from checking to Chase
+    txn1 = Transaction(
+        date=datetime.date(2026, 1, 29), amount=-1461.35,
+        description="CHASE CREDIT CRD EPAY", raw_description="CHASE CREDIT CRD EPAY 260128 9077835526 ANDREW B CONLON",
+        account_id=checking.id,
+    )
+    txn2 = Transaction(
+        date=datetime.date(2026, 1, 28), amount=1461.35,
+        description="Payment Thank You - Web", raw_description="Payment Thank You - Web",
+        account_id=chase.id,
+    )
+    session.add_all([txn1, txn2])
+    session.commit()
+
+    detector = TransferDetector(session)
+    pairs = detector.detect()
+    assert len(pairs) == 1
+    assert pairs[0]["amount"] == 1461.35
+
+
+def test_detect_marks_transfers():
+    session = make_session()
+    member = HouseholdMember(name="Andrew", relationship="self")
+    session.add(member)
+    session.flush()
+    checking = Account(name="Checking", institution="WF", account_type="checking", owner_id=member.id)
+    chase = Account(name="Chase", institution="Chase", account_type="credit", owner_id=member.id)
+    session.add_all([checking, chase])
+    session.flush()
+
+    txn1 = Transaction(
+        date=datetime.date(2026, 1, 29), amount=-1461.35,
+        description="CHASE CREDIT CRD EPAY", account_id=checking.id,
+    )
+    txn2 = Transaction(
+        date=datetime.date(2026, 1, 28), amount=1461.35,
+        description="Payment Thank You - Web", account_id=chase.id,
+    )
+    session.add_all([txn1, txn2])
+    session.commit()
+
+    detector = TransferDetector(session)
+    detector.mark_transfers()
+
+    session.refresh(txn1)
+    session.refresh(txn2)
+    assert txn1.is_transfer is True
+    assert txn2.is_transfer is True
+
+
+def test_no_false_positive_different_amounts():
+    session = make_session()
+    member = HouseholdMember(name="Andrew", relationship="self")
+    session.add(member)
+    session.flush()
+    checking = Account(name="Checking", institution="WF", account_type="checking", owner_id=member.id)
+    chase = Account(name="Chase", institution="Chase", account_type="credit", owner_id=member.id)
+    session.add_all([checking, chase])
+    session.flush()
+
+    txn1 = Transaction(
+        date=datetime.date(2026, 1, 29), amount=-1461.35,
+        description="CHASE CREDIT CRD EPAY", account_id=checking.id,
+    )
+    txn2 = Transaction(
+        date=datetime.date(2026, 1, 28), amount=500.00,
+        description="Payment Thank You - Web", account_id=chase.id,
+    )
+    session.add_all([txn1, txn2])
+    session.commit()
+
+    detector = TransferDetector(session)
+    pairs = detector.detect()
+    assert len(pairs) == 0