From c6dc266f2fd59a8c05623d12631466d148bcda8a Mon Sep 17 00:00:00 2001
From: YeonGyu-Kim <code.yeon.gyu@gmail.com>
Date: Wed, 20 May 2026 13:33:05 +0900
Subject: [PATCH] test(test-isolation): add diagnostic regression test for
 cross-suite leak

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
---
 .../rules-injector/test-isolation.test.ts     | 25 +++++++++++++++++++
 1 file changed, 25 insertions(+)
 create mode 100644 src/hooks/rules-injector/test-isolation.test.ts

diff --git a/src/hooks/rules-injector/test-isolation.test.ts b/src/hooks/rules-injector/test-isolation.test.ts
new file mode 100644
index 000000000..44e71ad0a
--- /dev/null
+++ b/src/hooks/rules-injector/test-isolation.test.ts
@@ -0,0 +1,25 @@
+import { beforeEach, describe, expect, it } from "bun:test";
+import { existsSync, readdirSync } from "node:fs";
+import { RULES_INJECTOR_STORAGE } from "./constants";
+
+function readStorageEntries(): readonly string[] {
+	if (!existsSync(RULES_INJECTOR_STORAGE)) return [];
+	return readdirSync(RULES_INJECTOR_STORAGE);
+}
+
+describe("rules injector test isolation", () => {
+	beforeEach(() => {
+		const leakedEntries = readStorageEntries();
+		expect(leakedEntries).toEqual([]);
+	});
+
+	it("#given the shared test setup runs #then persisted injected-rule state starts empty", () => {
+		// given: test-setup beforeEach has already run
+
+		// when
+		const entries = readStorageEntries();
+
+		// then
+		expect(entries).toEqual([]);
+	});
+});