Free TUI test renderers that were leaking TextBuffers (CL-5539)

list-modal.test.ts and provider-connect.test.ts never destroyed the
harness renderer they created. provider-setup.test.ts was worse: ~30
mountSetup/mountLogin/createHarness call sites but only one
harness.destroy() in the whole file, so nearly every test in it leaked
a renderer and its TextBuffer. mouse-reporting-disabled.test.ts only
freed its harness on the happy path, leaking on assertion failure.

Fix: track every harness created in each file and free it in a shared
afterEach, so cleanup happens regardless of which assertion fails
partway through a test, matching the pattern already used elsewhere in
this suite.

Author: TheGreatAxios

src/tui/list-modal.test.ts

@@ -1,20 +1,27 @@
-import { describe, expect, test } from "bun:test";
+import { afterEach, describe, expect, test } from "bun:test";
 
-import { createHarness } from "./harness.js";
+import { createHarness, type Harness } from "./harness.js";
 import { runListModal } from "./list-modal.js";
 
+let harness: Harness | undefined;
+
+afterEach(() => {
+  harness?.destroy();
+  harness = undefined;
+});
+
 async function mountModal(): Promise<{
   choice: Promise<string | null>;
-  harness: Awaited<ReturnType<typeof createHarness>>;
+  harness: Harness;
 }> {
-  const harness = await createHarness({ width: 80, height: 24 });
+  harness = await createHarness({ width: 80, height: 24 });
   const choice = runListModal({
     title: "resume session",
     options: [
       { id: "s-1", label: "First session" },
       { id: "s-2", label: "Second session" },
     ],
-    createRenderer: async () => harness.renderer,
+    createRenderer: async () => harness!.renderer,
   });
   await harness.renderOnce();
   return { choice, harness };

src/tui/mouse-reporting-disabled.test.ts

@@ -7,7 +7,7 @@
  * `createCliRenderer` branch runs, and assert on the options it was
  * actually called with.
  */
-import { afterAll, describe, expect, mock, test } from "bun:test";
+import { afterAll, afterEach, describe, expect, mock, test } from "bun:test";
 import type { Harness } from "./harness.js";
 
 interface CapturedRendererOptions {
@@ -49,6 +49,11 @@ afterAll(() => {
   mock.module("@opentui/core", () => realCore);
 });
 
+afterEach(() => {
+  let harness: Harness | undefined;
+  while ((harness = mountedHarnesses.pop()) !== undefined) harness.destroy();
+});
+
 const { runListModal } = await import("./list-modal.js");
 const { runProviderSetup } = await import("./provider-setup.js");
 
@@ -71,7 +76,6 @@ describe("default renderer mount disables DEC mouse reporting (CL-5540)", () =>
     expect(capturedOptions).toHaveLength(1);
     expect(capturedOptions[0]?.useMouse).toBe(false);
     expect(capturedOptions[0]?.enableMouseMovement).toBe(false);
-    mountedHarnesses.pop()?.destroy();
   });
 
   test("runProviderSetup", async () => {

src/tui/provider-connect.test.ts

@@ -1,9 +1,9 @@
-import { describe, test, expect } from "bun:test";
+import { afterEach, describe, test, expect } from "bun:test";
 import { mkdtemp, rm } from "node:fs/promises";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
 
-import { createHarness } from "./harness.js";
+import { createHarness, type Harness } from "./harness.js";
 import { connectProviderInline } from "./provider-connect.js";
 import { loadSettings } from "../config/settings.js";
 
@@ -12,17 +12,24 @@ import { loadSettings } from "../config/settings.js";
 // pins that an empty key on a key-required preset is rejected here too,
 // rather than silently downgraded to a keyless credential.
 describe("connectProviderInline", () => {
+  let harness: Harness | undefined;
+
+  afterEach(() => {
+    harness?.destroy();
+    harness = undefined;
+  });
+
   test("rejects an empty key on a key-required preset without persisting", async () => {
     const dir = await mkdtemp(join(tmpdir(), "provider-connect-"));
     const settingsPath = join(dir, "settings.json");
     try {
-      const harness = await createHarness({ width: 80, height: 30 });
+      harness = await createHarness({ width: 80, height: 30 });
       const resultPromise = connectProviderInline({
         providerId: "openai",
         settingsPath,
         localSettingsPath: join(dir, "local.json"),
         existing: null,
-        createRenderer: async () => harness.renderer,
+        createRenderer: async () => harness!.renderer,
       });
       await harness.renderOnce();
 

src/tui/provider-setup.test.ts

@@ -1,6 +1,6 @@
-import { describe, expect, test } from "bun:test";
+import { afterEach, describe, expect, test } from "bun:test";
 
-import { createHarness, type Harness } from "./harness.js";
+import { createHarness as createRawHarness, type Harness } from "./harness.js";
 import {
   addProviderSelectorChoices,
   connectedAccountCount,
@@ -41,6 +41,20 @@ const EMPTY: ProviderFormValues = {
   oauthProfile: "",
 };
 
+// This file mounts a fresh renderer per test; track every one so a single
+// afterEach can free them regardless of which assertion in a test fails.
+const activeHarnesses: Harness[] = [];
+
+async function createHarness(opts: { width: number; height: number }): Promise<Harness> {
+  const harness = await createRawHarness(opts);
+  activeHarnesses.push(harness);
+  return harness;
+}
+
+afterEach(() => {
+  while (activeHarnesses.length > 0) activeHarnesses.pop()!.destroy();
+});
+
 describe("provider setup pure helpers", () => {
   test("only the API key may be left blank", () => {
     expect(stepReady("name", "")).toBe(false);
@@ -1047,23 +1061,19 @@ describe("runProviderSetup paste", () => {
     const { done, harness } = await mountSetup(async (values) => {
       seen = values;
     });
-    try {
-      await pickRow(harness, PROVIDER_IDS, "openai");
-      await flush(harness);
-      harness.pressKey("Enter");
-      await harness.renderOnce();
-      await harness.mockInput.pasteBracketedText(key);
-      await harness.renderOnce();
-      const frame = harness.captureCharFrame();
-      harness.pressKey("Enter");
-      await harness.renderOnce();
-      harness.pressKey("Enter");
-      await harness.renderOnce();
-      await done;
-      return { values: seen, frame };
-    } finally {
-      harness.destroy();
-    }
+    await pickRow(harness, PROVIDER_IDS, "openai");
+    await flush(harness);
+    harness.pressKey("Enter");
+    await harness.renderOnce();
+    await harness.mockInput.pasteBracketedText(key);
+    await harness.renderOnce();
+    const frame = harness.captureCharFrame();
+    harness.pressKey("Enter");
+    await harness.renderOnce();
+    harness.pressKey("Enter");
+    await harness.renderOnce();
+    await done;
+    return { values: seen, frame };
   }
 
   test("a pasted key lands in the field, never echoed in the clear", async () => {