feat(sp39): Resubmission model + migration 0021 + idempotency tests

backend/tests/test_db_migrate.py

@@ -127,14 +127,15 @@ def test_migration_latest_idempotent_on_fresh_db(tmp_path: Path) -> None:
     SP32 bumped it to 19 with rendering_provider_npi +
     service_provider_npi on claims and remittances.
     SP37 bumped it to 20 with batch transaction_set_control_number.
+    SP39 bumped it to 21 with the resubmissions audit table.
     """
     engine = _fresh_engine(tmp_path)
     db_migrate.run(engine)
     v_after_first = _user_version(engine)
-    assert v_after_first == 20, f"expected head=20, got {v_after_first}"
+    assert v_after_first == 21, f"expected head=21, got {v_after_first}"
 
     db_migrate.run(engine)
-    assert _user_version(engine) == 20, "second run should not bump version"
+    assert _user_version(engine) == 21, "second run should not bump version"
 
 
 def test_drop_claims_unique_constraint_migration(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
@@ -160,7 +161,7 @@ def test_drop_claims_unique_constraint_migration(tmp_path: Path, monkeypatch: py
     engine = _fresh_engine(tmp_path)
 
     db_migrate.run(engine)
-    assert _user_version(engine) == 20, f"expected head=20, got {_user_version(engine)}"
+    assert _user_version(engine) == 21, f"expected head=21, got {_user_version(engine)}"
 
     # Two claims in one batch with the same patient_control_number
     # must be insertable. If 0015's table recreation re-introduced a
@@ -187,3 +188,50 @@ def test_drop_claims_unique_constraint_migration(tmp_path: Path, monkeypatch: py
         assert [r[0] for r in rows] == ["CLM-1", "CLM-2"]
         assert [float(r[1]) for r in rows] == [100.0, 200.0]
 
+
+
+# ---------------------------------------------------------------------------
+# SP39: migration 0021 creates the resubmissions table
+# ---------------------------------------------------------------------------
+
+
+def test_migration_0021_creates_resubmissions_table(tmp_path: Path) -> None:
+    """SP39: 0021_resubmissions.sql adds the resubmissions audit table
+    with the documented columns + unique constraint on
+    (claim_id, interchange_control_number)."""
+    # Point the runner at the REAL migrations dir so we exercise 0021.
+    real_dir = Path(db_migrate.__file__).parent / "migrations"
+    import cyclone.db_migrate as real_migrate_mod
+    real_dir_str = str(real_dir)
+
+    engine = _fresh_engine(tmp_path)
+    # monkeypatch the module-level MIGRATIONS_DIR
+    import importlib
+    monkey_save = real_migrate_mod.MIGRATIONS_DIR
+    real_migrate_mod.MIGRATIONS_DIR = Path(real_dir_str)
+    try:
+        db_migrate.run(engine)
+    finally:
+        real_migrate_mod.MIGRATIONS_DIR = monkey_save
+
+    # Verify the table exists with the expected columns + unique index.
+    with engine.connect() as conn:
+        version = conn.exec_driver_sql("PRAGMA user_version").scalar()
+        assert version >= 21
+        cols = conn.exec_driver_sql(
+            "PRAGMA table_info(resubmissions)"
+        ).all()
+        col_names = {row[1] for row in cols}
+        assert col_names == {
+            "id", "claim_id", "batch_id", "resubmitted_at",
+            "source_corrected_path",
+            "interchange_control_number", "group_control_number",
+        }
+        idx_rows = conn.exec_driver_sql(
+            "SELECT name, sql FROM sqlite_master "
+            "WHERE type='index' AND tbl_name='resubmissions'"
+        ).all()
+        idx_names = {row[0] for row in idx_rows}
+        assert "ix_resubmissions_claim_id" in idx_names
+        assert "ix_resubmissions_batch_id" in idx_names
+        assert "ux_resubmissions_claim_icn" in idx_names