🏆 test: optimize test suite with FakeTimers and race condition fixes (#1284)

* fix: exclude prompt/permission from plan agent config

plan agent should only inherit model settings from prometheus,
not the prompt or permission. This ensures plan agent uses
OpenCode's default behavior while only overriding the model.

* test(todo-continuation-enforcer): use FakeTimers for 15x faster tests

- Add custom FakeTimers implementation (~100 lines)
- Replace all real setTimeout waits with fakeTimers.advanceBy()
- Test time: 104.6s → 7.01s

* test(callback-server): fix race conditions with Promise.all and Bun.fetch

- Use Bun.fetch.bind(Bun) to avoid globalThis.fetch mock interference
- Use Promise.all pattern for concurrent fetch/waitForCallback
- Add Bun.sleep(10) in afterEach for port release

* test(concurrency): replace placeholder assertions with getCount checks

Replace 6 meaningless expect(true).toBe(true) assertions with
actual getCount() verifications for test quality improvement

* refactor(config-handler): simplify planDemoteConfig creation

Remove unnecessary IIFE and destructuring, use direct spread instead

* test(executor): use FakeTimeouts for faster tests

- Add custom FakeTimeouts implementation
- Replace setTimeout waits with fakeTimeouts.advanceBy()
- Test time reduced from ~26s to ~6.8s

* test: fix gemini model mock for artistry unstable mode

* test: fix model list mock payload shape

* test: mock provider models for artistry category

---------

Co-authored-by: justsisyphus <justsisyphus@users.noreply.github.com>

src/features/background-agent/concurrency.test.ts

@@ -176,8 +176,8 @@ describe("ConcurrencyManager.acquire/release", () => {
     await manager.acquire("model-a")
     await manager.acquire("model-a")
 
-    // #then - both resolved without waiting
-    expect(true).toBe(true)
+    // #then - both resolved without waiting, count should be 2
+    expect(manager.getCount("model-a")).toBe(2)
   })
 
   test("should allow acquires up to default limit of 5", async () => {
@@ -190,8 +190,8 @@ describe("ConcurrencyManager.acquire/release", () => {
     await manager.acquire("model-a")
     await manager.acquire("model-a")
 
-    // #then - all 5 resolved
-    expect(true).toBe(true)
+    // #then - all 5 resolved, count should be 5
+    expect(manager.getCount("model-a")).toBe(5)
   })
 
   test("should queue when limit reached", async () => {
@@ -276,8 +276,8 @@ describe("ConcurrencyManager.acquire/release", () => {
     manager.release("model-a")
     await manager.acquire("model-a")
 
-    // #then
-    expect(true).toBe(true)
+    // #then - count should be 1 after re-acquiring
+    expect(manager.getCount("model-a")).toBe(1)
   })
 
   test("should handle release when no acquire", () => {
@@ -288,21 +288,21 @@ describe("ConcurrencyManager.acquire/release", () => {
     // #when - release without acquire
     manager.release("model-a")
 
-    // #then - should not throw
-    expect(true).toBe(true)
+    // #then - count should be 0 (no negative count)
+    expect(manager.getCount("model-a")).toBe(0)
   })
 
   test("should handle release when no prior acquire", () => {
     // #given - default config
 
-    // #when - release without acquire
-    manager.release("model-a")
+     // #when - release without acquire
+     manager.release("model-a")
 
-    // #then - should not throw
-    expect(true).toBe(true)
-  })
+     // #then - count should be 0 (no negative count)
+     expect(manager.getCount("model-a")).toBe(0)
+   })
 
-  test("should handle multiple acquires and releases correctly", async () => {
+   test("should handle multiple acquires and releases correctly", async () => {
     // #given
     const config: BackgroundTaskConfig = { defaultConcurrency: 3 }
     manager = new ConcurrencyManager(config)
@@ -317,11 +317,11 @@ describe("ConcurrencyManager.acquire/release", () => {
     manager.release("model-a")
     manager.release("model-a")
 
-    // Should be able to acquire again
-    await manager.acquire("model-a")
+     // Should be able to acquire again
+     await manager.acquire("model-a")
 
-    // #then
-    expect(true).toBe(true)
+     // #then - count should be 1 after re-acquiring
+     expect(manager.getCount("model-a")).toBe(1)
   })
 
   test("should use model-specific limit for acquire", async () => {