Add first account cumsize test; known to fail Bo

tests/test_accounting.py

@@ -8,7 +8,15 @@
 from pathlib import Path
 
 from piker import config
-from piker.accounting import load_account
+from piker.accounting import (
+    Account,
+    calc,
+    Position,
+    TransactionLedger,
+    open_trade_ledger,
+    load_account,
+    load_account_from_ledger,
+)
 
 
 def test_root_conf_networking_section(
@@ -34,3 +42,53 @@ def test_account_file_default_empty(
     assert not conf
     assert path.parent.is_dir()
     assert path.parent.name == 'accounting'
+
+
+def test_paper_ledger_position_calcs():
+    broker: str = 'binance'
+    acnt_name: str = 'paper'
+
+    accounts_path: Path = config.repodir() / 'tests' / '_inputs'
+
+    ldr: TransactionLedger
+    with (
+        open_trade_ledger(
+            broker,
+            acnt_name,
+            allow_from_sync_code=True,
+
+            _fp=accounts_path,
+        ) as ldr,
+
+        # open `polars` acnt dfs Bo
+        calc.open_ledger_dfs(
+            broker,
+            acnt_name,
+            ledger=ldr,
+
+            _fp=accounts_path,
+
+        ) as (dfs, ledger),
+
+    ):
+        acnt: Account = load_account_from_ledger(
+            broker,
+            acnt_name,
+            ledger=ldr,
+            _fp=accounts_path,
+        )
+
+        # do manual checks on expected pos calcs based on input
+        # ledger B)
+
+        # xrpusdt should have a net-zero size
+        xrp: str = 'xrpusdt.spot.binance'
+        pos: Position = acnt.pps[xrp]
+
+        # XXX: turns out our old dict-style-processing
+        # get's this wrong i think due to dt-sorting..
+        # lcum: float = pos.cumsize
+
+        df = dfs[xrp]
+        assert df['cumsize'][-1] == 0
+        assert pos.cumsize == 0