test(windows): cover teardown decisions deterministically

packages/lsp/lsp-local/tests/connection.spec.ts

@@ -5,6 +5,7 @@ import {
   signalProcessGroup,
   signalProcessTree,
   taskkillProcessTree,
+  waitForTreeExit,
 } from '@deepseek-ai/dsh-lsp-local/src/connection.ts'
 import type {
   ConnectionWriter,
@@ -248,6 +249,19 @@ describe('process-tree signaling', () => {
     expect(run).toHaveBeenCalledWith(-42, 'SIGKILL')
   })
 
+  it('waits for tree exit and stops when its bound aborts', async () => {
+    const isAlive = vi.fn()
+      .mockReturnValueOnce(true)
+      .mockReturnValue(false)
+    const yieldNow = vi.fn(() => Promise.resolve())
+    await expect(waitForTreeExit(isAlive, undefined, yieldNow)).resolves.toBe(true)
+    expect(yieldNow).toHaveBeenCalledOnce()
+
+    const controller = new AbortController()
+    controller.abort()
+    await expect(waitForTreeExit(() => true, controller.signal, yieldNow)).resolves.toBe(false)
+  })
+
   it('uses taskkill for a Windows tree and a negative pid for a POSIX group', () => {
     const operations = fakeProcessTreeOperations()
     signalProcessTree('win32', 42, 'SIGTERM', operations)

packages/lsp/lsp-local/tests/instance.spec.ts

@@ -1,4 +1,4 @@
-import { afterEach, beforeEach, describe, expect, it } from 'vitest'
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
 import { mkdtemp, mkdir, readFile, rm, writeFile, realpath } from 'node:fs/promises'
 import { tmpdir } from 'node:os'
 import { join } from 'node:path'
@@ -6,6 +6,7 @@ import { pathToFileURL, fileURLToPath } from 'node:url'
 import { LspInstance, readHostSource } from '@deepseek-ai/dsh-lsp-local'
 import { encodeMessage } from '@deepseek-ai/dsh-lsp-local'
 import type { ConnectionWriter } from '@deepseek-ai/dsh-lsp-local/src/connection.ts'
+import { escalateProcessTree } from '@deepseek-ai/dsh-lsp-local/src/instance.ts'
 import type { InstanceSpec } from '@deepseek-ai/dsh-lsp-local/src/instance.ts'
 import type { LspProviderQuery, LspQueryResult } from '@deepseek-ai/dsh-lsp'
 
@@ -242,6 +243,14 @@ describe('LspInstance query and abort', () => {
 })
 
 describe('LspInstance disposal', () => {
+  it('escalates only when the process tree survives its grace period', () => {
+    const forceKill = vi.fn()
+    escalateProcessTree(false, forceKill)
+    expect(forceKill).toHaveBeenCalledOnce()
+    escalateProcessTree(true, forceKill)
+    expect(forceKill).toHaveBeenCalledOnce()
+  })
+
   it('lets a server finish protocol exit before signal escalation', async () => {
     const marker = join(root, 'graceful-exit.log')
     const instance = makeInstance({