fix(test): use proper function syntax for Vitest constructor mocks

Vitest requires mocks used as constructors to use 'function' keyword
instead of arrow functions. This fixes 15 failing unit tests across
two test files.

Changes:
- providers.test.mts: Use vi.fn(function() {...}) for Gitlab mock
- config.test.mts: Replace all arrow functions with proper function
  syntax in mock implementations

All 25 tests in both files now pass successfully.

Author: jdalton

packages/cli/src/utils/git/providers.test.mts

@@ -24,17 +24,19 @@ vi.mock('./operations.mts', () => ({
 }))
 
 vi.mock('@gitbeaker/rest', () => ({
-  Gitlab: vi.fn().mockImplementation(() => ({
-    MergeRequests: {
-      create: vi.fn(),
-      show: vi.fn(),
-      rebase: vi.fn(),
-      all: vi.fn(),
-    },
-    MergeRequestNotes: {
-      create: vi.fn(),
-    },
-  })),
+  Gitlab: vi.fn(function () {
+    return {
+      MergeRequests: {
+        create: vi.fn(),
+        show: vi.fn(),
+        rebase: vi.fn(),
+        all: vi.fn(),
+      },
+      MergeRequestNotes: {
+        create: vi.fn(),
+      },
+    }
+  }),
 }))
 
 describe('provider-factory', () => {

packages/cli/src/utils/npm/config.test.mts

@@ -1,30 +1,24 @@
 import { beforeEach, describe, expect, it, vi } from 'vitest'
 
-// Create mock constructor and instance in hoisted scope
-const { MockNpmConfig, mockNpmConfigInstance } = vi.hoisted(() => {
-  const mockNpmConfigInstance = {
-    load: vi.fn().mockResolvedValue(undefined),
-    flat: {
-      registry: 'https://registry.npmjs.org/',
-      cache: '/home/user/.npm',
-      prefix: '/usr/local',
-    },
-  }
-
-  // Create a proper constructor function that vitest can mock
-  function MockNpmConfig() {
-    return mockNpmConfigInstance
-  }
-
-  return { MockNpmConfig: vi.fn(MockNpmConfig), mockNpmConfigInstance }
-})
+// Create mock instance that will be returned by constructor
+const mockNpmConfigInstance = {
+  load: vi.fn().mockResolvedValue(undefined),
+  flat: {
+    registry: 'https://registry.npmjs.org/',
+    cache: '/home/user/.npm',
+    prefix: '/usr/local',
+  },
+}
 
 // Mock @npmcli/config.
 vi.mock('@npmcli/config', () => ({
-  default: MockNpmConfig,
+  default: vi.fn(function () {
+    return mockNpmConfigInstance
+  }),
 }))
 
 import { getNpmConfig } from './config.mts'
+import NpmConfig from '@npmcli/config'
 
 // Mock @npmcli/config/lib/definitions.
 vi.mock('@npmcli/config/lib/definitions', () => ({
@@ -38,11 +32,15 @@ vi.mock('./paths.mts', () => ({
   getNpmDirPath: vi.fn(() => '/usr/local/lib/node_modules/npm'),
 }))
 
+const MockNpmConfig = vi.mocked(NpmConfig)
+
 describe('npm-config utilities', () => {
   beforeEach(() => {
     // Clear mock calls and restore original implementation
     MockNpmConfig.mockClear()
-    MockNpmConfig.mockImplementation(() => mockNpmConfigInstance)
+    MockNpmConfig.mockImplementation(function () {
+      return mockNpmConfigInstance
+    })
     vi.mocked(mockNpmConfigInstance.load).mockClear()
   })
 
@@ -143,7 +141,9 @@ describe('npm-config utilities', () => {
         flat: { test: 'value' },
       }
       vi.mocked((await import('@npmcli/config')).default).mockImplementation(
-        () => mockConfigInstance,
+        function () {
+          return mockConfigInstance
+        },
       )
 
       await getNpmConfig()