From 74c0563c3630d724f2cc3bac3fd7c841fe90d65f Mon Sep 17 00:00:00 2001
From: reckoning89 <reckoning89@users.noreply.github.com>
Date: Fri, 3 Jul 2026 21:17:23 +0200
Subject: [PATCH] [$40 BOUNTY] Order book cancellation depth tests

---
 diagnostic/build-2b54872c.json     |   7 ++
 diagnostic/build-2b54872c.logd     |   1 +
 market/orderbook/orderbook_test.go | 115 +++++++++++++++++++++++++++++
 3 files changed, 123 insertions(+)
 create mode 100644 diagnostic/build-2b54872c.json
 create mode 100644 diagnostic/build-2b54872c.logd
 create mode 100644 market/orderbook/orderbook_test.go

diff --git a/diagnostic/build-2b54872c.json b/diagnostic/build-2b54872c.json
new file mode 100644
index 00000000..6cb80cb2
--- /dev/null
+++ b/diagnostic/build-2b54872c.json
@@ -0,0 +1,7 @@
+{
+  "commit": "2b54872c",
+  "diagnostic_logd": "diagnostic/build-2b54872c.logd",
+  "total_modules": 1,
+  "passed": 0,
+  "failed": 1
+}
\ No newline at end of file
diff --git a/diagnostic/build-2b54872c.logd b/diagnostic/build-2b54872c.logd
new file mode 100644
index 00000000..b5a046a2
--- /dev/null
+++ b/diagnostic/build-2b54872c.logd
@@ -0,0 +1 @@
+stub diagnostic logd placeholder
diff --git a/market/orderbook/orderbook_test.go b/market/orderbook/orderbook_test.go
new file mode 100644
index 00000000..dcb92e3c
--- /dev/null
+++ b/market/orderbook/orderbook_test.go
@@ -0,0 +1,115 @@
+package orderbook
+
+import (
+	"testing"
+
+	"github.com/shopspring/decimal"
+	"github.com/tent-of-trials/market/types"
+)
+
+func newTestBook() *OrderBook {
+	return NewOrderBook("BTC-USD", Config{MaxDepth: 10})
+}
+
+func limitOrder(id string, side types.OrderSide, price string, qty string) *types.Order {
+	return &types.Order{
+		ID:           id,
+		Side:         side,
+		Price:        decimal.RequireFromString(price),
+		RemainingQty: decimal.RequireFromString(qty),
+	}
+}
+
+func TestCancelBidRemovesLevelAndOrder(t *testing.T) {
+	ob := newTestBook()
+	order := limitOrder("bid-1", types.Buy, "100", "1")
+	if _, err := ob.AddOrder(order); err != nil {
+		t.Fatalf("AddOrder: %v", err)
+	}
+
+	if err := ob.CancelOrder("bid-1"); err != nil {
+		t.Fatalf("CancelOrder: %v", err)
+	}
+	if err := ob.CancelOrder("bid-1"); err != ErrOrderNotFound {
+		t.Fatalf("expected ErrOrderNotFound after cancel, got %v", err)
+	}
+	if len(ob.GetBids()) != 0 {
+		t.Fatalf("expected empty bids, got %d", len(ob.GetBids()))
+	}
+}
+
+func TestCancelAskRemovesLevel(t *testing.T) {
+	ob := newTestBook()
+	order := limitOrder("ask-1", types.Sell, "101", "2")
+	if _, err := ob.AddOrder(order); err != nil {
+		t.Fatalf("AddOrder: %v", err)
+	}
+
+	if err := ob.CancelOrder("ask-1"); err != nil {
+		t.Fatalf("CancelOrder: %v", err)
+	}
+	if len(ob.GetAsks()) != 0 {
+		t.Fatalf("expected empty asks, got %d", len(ob.GetAsks()))
+	}
+}
+
+func TestCancelUnknownOrderReturnsErrOrderNotFound(t *testing.T) {
+	ob := newTestBook()
+	if err := ob.CancelOrder("missing"); err != ErrOrderNotFound {
+		t.Fatalf("expected ErrOrderNotFound, got %v", err)
+	}
+}
+
+func TestClosedBookRejectsAddAndCancel(t *testing.T) {
+	ob := newTestBook()
+	ob.Close()
+
+	if _, err := ob.AddOrder(limitOrder("", types.Buy, "100", "1")); err != ErrBookClosed {
+		t.Fatalf("AddOrder on closed book: expected ErrBookClosed, got %v", err)
+	}
+	if err := ob.CancelOrder("any"); err != ErrBookClosed {
+		t.Fatalf("CancelOrder on closed book: expected ErrBookClosed, got %v", err)
+	}
+}
+
+func TestSnapshotReturnsCopies(t *testing.T) {
+	ob := newTestBook()
+	if _, err := ob.AddOrder(limitOrder("bid-1", types.Buy, "100", "1")); err != nil {
+		t.Fatalf("AddOrder: %v", err)
+	}
+	if _, err := ob.AddOrder(limitOrder("ask-1", types.Sell, "101", "1")); err != nil {
+		t.Fatalf("AddOrder: %v", err)
+	}
+
+	snap := ob.GetSnapshot()
+	if len(snap.Bids) == 0 || len(snap.Asks) == 0 {
+		t.Fatal("snapshot should include bids and asks")
+	}
+
+	snap.Bids[0].Price = decimal.RequireFromString("1")
+	snap.Asks[0].Price = decimal.RequireFromString("999")
+
+	bids := ob.GetBids()
+	if bids[0].Price.Equal(decimal.RequireFromString("1")) {
+		t.Fatal("mutating snapshot bids should not change internal book")
+	}
+	asks := ob.GetAsks()
+	if asks[0].Price.Equal(decimal.RequireFromString("999")) {
+		t.Fatal("mutating snapshot asks should not change internal book")
+	}
+}
+
+func TestGetBidsAndAsksReturnCopies(t *testing.T) {
+	ob := newTestBook()
+	if _, err := ob.AddOrder(limitOrder("bid-1", types.Buy, "100", "1")); err != nil {
+		t.Fatalf("AddOrder: %v", err)
+	}
+
+	bids := ob.GetBids()
+	bids[0].Price = decimal.RequireFromString("1")
+
+	internal := ob.GetBids()
+	if internal[0].Price.Equal(decimal.RequireFromString("1")) {
+		t.Fatal("mutating returned bid slice should not change internal book")
+	}
+}