test: strengthen golden worktree setup verification

- Track working directory in git call inspection to verify correct execution context
- Verify user.name/email config applies to worktree-specific settings, not repo
- Add exhaustive setup call sequence assertions to catch setup/rollback leaks

tests/e2e/helpers/golden-source-control.unit.test.ts

@@ -1,18 +1,53 @@
 import { execFileSync } from 'node:child_process'
+import os from 'node:os'
+import path from 'node:path'
 import { beforeEach, describe, expect, it, vi } from 'vitest'
-import { createGoldenWorktree } from './golden-source-control'
+import {
+  createGoldenWorktree,
+  GOLDEN_GIT_AUTHOR_EMAIL,
+  GOLDEN_GIT_AUTHOR_NAME
+} from './golden-source-control'
 
 vi.mock('node:child_process', () => ({ execFileSync: vi.fn() }))
 
 const execFileSyncMock = vi.mocked(execFileSync)
-const gitArgsFor = (): string[][] =>
-  execFileSyncMock.mock.calls.map(([, args]) => (args ?? []) as string[])
+
+type GitCall = { args: string[]; cwd?: string }
+
+/** Setup runs in the new worktree while rollback runs in the repo, so cwd is part of the contract. */
+const gitCallsFor = (): GitCall[] =>
+  execFileSyncMock.mock.calls.map(([, args, options]) => ({
+    args: (args ?? []) as string[],
+    cwd: (options as { cwd?: string } | undefined)?.cwd
+  }))
+
+/** Args-only view for lookups that locate a call rather than assert its full shape. */
+const gitArgsFor = (): string[][] => gitCallsFor().map((call) => call.args)
+
+/** Returns the thrown value itself; `toThrow` only compares messages, not identity. */
+const captureThrow = (run: () => void): unknown => {
+  try {
+    run()
+    return undefined
+  } catch (error) {
+    return error
+  }
+}
+
+/** The worktree path and branch name are randomly suffixed, so read them back off the add call. */
+const worktreeAddTargets = (): { branchName: string; worktreePath: string } => {
+  const addArgs = gitArgsFor().find((args) => args[0] === 'worktree' && args[1] === 'add')
+  expect(addArgs).toBeDefined()
+  const [, , worktreePath, , branchName] = addArgs as string[]
+  return { branchName, worktreePath }
+}
 
 describe('createGoldenWorktree', () => {
   beforeEach(() => {
     execFileSyncMock.mockReset()
   })
 
+  /** A half-built worktree leaks into later runs unless both the worktree and the branch go away. */
   it('rolls back the worktree and branch when a configuration command fails', () => {
     const setupError = new Error('git config --worktree unsupported')
     execFileSyncMock.mockImplementation(((_file: string, args: string[]) => {
@@ -22,15 +57,18 @@ describe('createGoldenWorktree', () => {
       return ''
     }) as unknown as typeof execFileSync)
 
-    expect(() => createGoldenWorktree('/repo', 'rollback')).toThrow(setupError)
+    expect(captureThrow(() => createGoldenWorktree('/repo', 'rollback'))).toBe(setupError)
 
-    const worktreePath = gitArgsFor().find((args) => args[0] === 'worktree')?.[2]
-    expect(worktreePath).toBeDefined()
-    const branchName = gitArgsFor().find((args) => args[0] === 'branch')?.[2]
-    expect(gitArgsFor()).toContainEqual(['worktree', 'remove', '--force', worktreePath])
+    const { branchName, worktreePath } = worktreeAddTargets()
     expect(branchName).toMatch(/^e2e-golden-rollback-/)
+    expect(gitCallsFor()).toContainEqual({
+      args: ['worktree', 'remove', '--force', worktreePath],
+      cwd: '/repo'
+    })
+    expect(gitCallsFor()).toContainEqual({ args: ['branch', '-D', branchName], cwd: '/repo' })
   })
 
+  /** Rollback must still be attempted in full, and its own failure must not mask the setup cause. */
   it('keeps the setup error when rollback itself fails', () => {
     const setupError = new Error('git config --worktree unsupported')
     execFileSyncMock.mockImplementation(((_file: string, args: string[]) => {
@@ -43,16 +81,37 @@ describe('createGoldenWorktree', () => {
       return ''
     }) as unknown as typeof execFileSync)
 
-    expect(() => createGoldenWorktree('/repo', 'rollback-fails')).toThrow(setupError)
+    expect(captureThrow(() => createGoldenWorktree('/repo', 'rollback-fails'))).toBe(setupError)
+
+    const { branchName, worktreePath } = worktreeAddTargets()
+    expect(branchName).toMatch(/^e2e-golden-rollback-fails-/)
+    expect(gitCallsFor()).toContainEqual({
+      args: ['worktree', 'remove', '--force', worktreePath],
+      cwd: '/repo'
+    })
+    expect(gitCallsFor()).toContainEqual({ args: ['branch', '-D', branchName], cwd: '/repo' })
   })
 
+  /** The identity config must land on the worktree, not the repo, or commits pick up the host author. */
   it('returns the fixture when every setup command succeeds', () => {
     execFileSyncMock.mockReturnValue('')
 
     const fixture = createGoldenWorktree('/repo', 'happy')
 
     expect(fixture.branchName).toMatch(/^e2e-golden-happy-/)
-    expect(gitArgsFor().some((args) => args[0] === 'worktree' && args[1] === 'remove')).toBe(false)
-    expect(gitArgsFor().some((args) => args[0] === 'branch')).toBe(false)
+    expect(fixture.worktreePath).toBe(path.join(os.tmpdir(), fixture.branchName))
+    // Exhaustive: also proves no rollback ran.
+    expect(gitCallsFor()).toEqual([
+      { args: ['worktree', 'add', fixture.worktreePath, '-b', fixture.branchName], cwd: '/repo' },
+      { args: ['config', 'extensions.worktreeConfig', 'true'], cwd: fixture.worktreePath },
+      {
+        args: ['config', '--worktree', 'user.name', GOLDEN_GIT_AUTHOR_NAME],
+        cwd: fixture.worktreePath
+      },
+      {
+        args: ['config', '--worktree', 'user.email', GOLDEN_GIT_AUTHOR_EMAIL],
+        cwd: fixture.worktreePath
+      }
+    ])
   })
 })