test(windows): close native coverage gaps

packages/credentials/credentials-local/src/index.ts

@@ -108,6 +108,7 @@ async function assertOwnerOnly(filename: string): Promise<void> {
     return
   }
   /* v8 ignore stop */
+  /* v8 ignore start -- Windows has no POSIX mode enforcement; POSIX behavior tests enforce this peer. */
   let mode: number
   try {
     mode = (await stat(filename)).mode
@@ -122,6 +123,7 @@ async function assertOwnerOnly(filename: string): Promise<void> {
     `credentials-local: ${filename} is readable beyond its owner (mode ${(mode & 0o777).toString(8)});`
     + ` run "chmod 600 ${filename}" before starting again`,
   )
+  /* v8 ignore stop */
 }
 
 /** Whether a filesystem error means absence; every non-ENOENT failure must surface. */

packages/pty/tool-bash-persistent/tests/tools.spec.ts

@@ -96,6 +96,7 @@ type StubMode =
   | 'send-error'
   | 'prompt-after-idle'
   | 'empty-page-after-latest'
+  | 'paged-scrollback'
 
 class StubPtySession implements PtyBackendSession {
   readonly motd = '__DSH_PERSISTENT_BASH_PROMPT__ '
@@ -211,6 +212,19 @@ class StubPtySession implements PtyBackendSession {
       return { text: '', totalLines: 2, lineBegin: 1, lineEnd: 1, truncated: false }
     }
     const lines = this.scrollback.split('\n')
+    if (this.mode === 'paged-scrollback') {
+      const offset = request.offset ?? 0
+      const end = lines.length - offset
+      const start = Math.max(0, end - 3)
+      const returnedLines = end - start
+      return {
+        text: lines.slice(start, end).join('\n'),
+        totalLines: lines.length,
+        lineBegin: offset,
+        lineEnd: offset + returnedLines,
+        truncated: this.historyTruncated,
+      }
+    }
     return {
       text: this.scrollback,
       totalLines: this.mode === 'empty-page-after-latest' ? lines.length + 1 : lines.length,
@@ -402,6 +416,16 @@ describe('tool-bash-persistent', () => {
     expect(text(await call(ctx, owner, 'empty continuation page'))).toContain('hello from stub')
   })
 
+  it('assembles retained output across backward scrollback pages', async () => {
+    const { ctx, owner, stub } = await setup({ backendType: 'stub', maxOutputChars: 1_000 })
+    await call(ctx, owner, 'warm up')
+    const session = stub.sessions[0]!
+    session.mode = 'paged-scrollback'
+    session.scrollback = ''
+
+    expect(text(await call(ctx, owner, 'paged output'))).toBe('hello from stub')
+  })
+
   it('sanitizes a prompt fallback reached after multiple polling rounds', async () => {
     const { ctx, owner, stub } = await setup({ backendType: 'stub', maxOutputChars: 1_000 })
     await call(ctx, owner, 'warm up')

packages/settings/settings-local/tests/local.spec.ts

@@ -137,6 +137,13 @@ describe('boot and reads', () => {
     await expect(boot({ path, watch: false })).rejects.toThrow(/EACCES|permission/i)
   })
 
+  it('fails loud when the document path names a directory', async () => {
+    const dir = await tempDir()
+    const path = join(dir, 'settings.yaml')
+    await mkdir(path)
+    await expect(boot({ path, watch: false })).rejects.toThrow(/EISDIR|directory/i)
+  })
+
   it('fails loud on an unsupported extension', async () => {
     const dir = await tempDir()
     await expect(boot({ path: join(dir, 'settings.toml'), watch: false }))

packages/storage/storage-sqlite/tests/sqlite-backend.spec.ts

@@ -217,6 +217,13 @@ describe('sqlite backend specifics', () => {
     await chmod(dir, 0o700)
   })
 
+  it('propagates an invalid database filename before opening SQLite', async () => {
+    const path = await freshDbPath()
+    const backend = backendAt(`${path}\0invalid`)
+    await expect(backend.kv.open(DESCRIPTOR)).rejects.toThrow(/null bytes/i)
+    await backend.close()
+  })
+
   it('preserves the mode of an existing database file', async () => {
     if (process.platform === 'win32') return
     const path = await freshDbPath()

packages/util/atomic-write/tests/atomic-write.spec.ts

@@ -2,7 +2,7 @@ import { lstat, mkdir, mkdtemp, readFile, readdir, stat, symlink, writeFile } fr
 import { tmpdir } from 'node:os'
 import { join } from 'node:path'
 import { describe, expect, it } from 'vitest'
-import { writeFileAtomic } from '../src/index.ts'
+import { withFileLock, writeFileAtomic } from '../src/index.ts'
 
 async function scratch(): Promise<string> {
   return mkdtemp(join(tmpdir(), 'dsh-atomic-write-'))
@@ -46,3 +46,17 @@ describe('writeFileAtomic', () => {
     expect((await readdir(dir)).filter(entry => entry.includes('.tmp'))).toEqual([])
   })
 })
+
+describe('withFileLock', () => {
+  it('rejects an invalid parent hierarchy before running the operation', async () => {
+    const dir = await scratch()
+    const parent = join(dir, 'not-a-directory')
+    await writeFile(parent, 'occupied')
+    let called = false
+
+    await expect(withFileLock(join(parent, 'document'), async () => {
+      called = true
+    })).rejects.toThrow(/ENOENT|ENOTDIR|not a directory/i)
+    expect(called).toBe(false)
+  })
+})