Fix mocking

Author: ehmicky

__mocks__/cpx.js

@@ -1,13 +1,18 @@
+const fs = require('fs')
 const path = require('path')
+const util = require('util')
+
 const nextOnNetlify = require('next-on-netlify')
 const { PHASE_PRODUCTION_BUILD } = require('next/constants')
 const { default: loadConfig } = require('next/dist/next-server/server/config')
-const makef = require('makef')
 const makeDir = require('make-dir')
 const pathExists = require('path-exists')
 const cpx = require('cpx')
+
 const isStaticExportProject = require('./helpers/isStaticExportProject')
 
+const pWriteFile = util.promisify(fs.writeFile)
+
 // * Helpful Plugin Context *
 // - Between the prebuild and build steps, the project's build command is run
 // - Between the build and postbuild steps, any functions are bundled
@@ -64,7 +69,7 @@ module.exports = {
             target: 'serverless'
           }
         `
-      makef.createFile({ 'next.config.js': nextConfig })
+      await pWriteFile('next.config.js', nextConfig)
       console.log(`** Adding next.config.js with target set to 'serverless' **`)
     }
   },

__mocks__/make-dir.js

@@ -26,7 +26,6 @@
   "dependencies": {
     "cpx": "^1.5.0",
     "make-dir": "^3.1.0",
-    "makef": "^1.0.0",
     "next": "^9.5.3",
     "next-on-netlify": "^2.6.0",
     "path-exists": "^4.0.0"
@@ -37,7 +36,8 @@
     "jest": "^26.6.1",
     "prettier": "^2.1.2",
     "react": "^17.0.1",
-    "react-dom": "^17.0.1"
+    "react-dom": "^17.0.1",
+    "tmp-promise": "^3.0.2"
   },
   "husky": {
     "hooks": {

__mocks__/makef.js

@@ -1,10 +1,13 @@
 const path = require('path')
 const process = require('process')
+
 const nextOnNetlify = require('next-on-netlify')
-const makef = require('makef')
-const makeDir = require('make-dir')
-const cpx = require('cpx')
-const plugin = require('../index')
+const pathExists = require('path-exists')
+const { dir: getTmpDir } = require('tmp-promise')
+
+const plugin = require('..')
+
+const FIXTURES_DIR = `${__dirname}/fixtures`
 
 const utils = {
   run: {
@@ -15,32 +18,44 @@ const utils = {
   },
 }
 
-afterEach(() => {
+// Temporary switch cwd
+const changeCwd = function (cwd) {
+  const originalCwd = process.cwd()
+  process.chdir(cwd)
+  return process.chdir.bind(process, originalCwd)
+}
+
+// Switch cwd to a fixture directory
+const useFixture = function (fixtureName) {
+  const fixtureDir = `${FIXTURES_DIR}/${fixtureName}`
+  const restoreCwd = changeCwd(fixtureDir)
+  return { restoreCwd, fixtureDir }
+}
+
+// In each test, we change cwd to a temporary directory.
+// This allows us not to have to mock filesystem operations.
+beforeEach(async () => {
+  const { path, cleanup } = await getTmpDir({ unsafeCleanup: true })
+  const restoreCwd = changeCwd(path)
+  Object.assign(this, { cleanup, restoreCwd })
+})
+
+afterEach(async () => {
   utils.build.failBuild.mockReset()
   utils.run.command.mockReset()
   jest.clearAllMocks()
   jest.resetAllMocks()
+
+  // Cleans up the temporary directory from `getTmpDir()` and do not make it
+  // the current directory anymore
+  this.restoreCwd()
+  await this.cleanup()
 })
 
 jest.mock('next-on-netlify')
-jest.mock('makef')
-jest.mock('make-dir')
-jest.mock('cpx')
-
-// See: https://github.com/tschaub/mock-fs/issues/234#issuecomment-377862172
-// for why this log is required
-console.log('Initializing tests')
 
 const DUMMY_PACKAGE_JSON = { name: 'dummy', version: '1.0.0' }
 
-const FIXTURES_DIR = `${__dirname}/fixtures`
-
-const useFixture = function (fixtureName) {
-  const originalCwd = process.cwd()
-  process.chdir(`${FIXTURES_DIR}/${fixtureName}`)
-  return process.chdir.bind(process, originalCwd)
-}
-
 describe('preBuild()', () => {
   test('fail build if the app has static html export in npm script', async () => {
     await plugin.onPreBuild({
@@ -102,19 +117,17 @@ describe('preBuild()', () => {
       constants: { FUNCTIONS_SRC: 'out_functions' },
     })
 
-    expect(makef.createFile.mock.calls.length).toEqual(1)
+    expect(await pathExists('next.config.js')).toBeTruthy()
   })
 
   test(`fail build if the app's next config has an invalid target`, async () => {
-    const restoreCwd = useFixture('invalid_next_config')
-
+    const { restoreCwd } = useFixture('invalid_next_config')
     await plugin.onPreBuild({
       netlifyConfig: {},
       packageJson: DUMMY_PACKAGE_JSON,
       utils,
       constants: { FUNCTIONS_SRC: 'out_functions' },
     })
-
     restoreCwd()
 
     const acceptableTargets = ['serverless', 'experimental-serverless-trace']
@@ -143,17 +156,19 @@ describe('onBuild()', () => {
       },
     })
 
-    expect(makeDir.mock.calls[0][0]).toEqual(PUBLISH_DIR)
+    expect(await pathExists(PUBLISH_DIR)).toBeTruthy()
   })
 
   test('calls copySync with correct args', async () => {
-    const PUBLISH_DIR = 'some/path'
+    const { restoreCwd, fixtureDir } = useFixture('publish_copy_files')
+    const PUBLISH_DIR = `${fixtureDir}/publish`
     await plugin.onBuild({
       constants: {
         PUBLISH_DIR,
       },
     })
+    restoreCwd()
 
-    expect(cpx.copySync.mock.calls[0][0]).toEqual('out_publish/**/*', PUBLISH_DIR)
+    expect(await pathExists(`${PUBLISH_DIR}/subdir/dummy.txt`)).toBeTruthy()
   })
 })