Investigate spec on mac (#7111)

* run scripts unit tests on Mac too

* build this branch on Mac on CircleCI

* skip some mock file system tests, run them only on Linux

* skip dynamically

* use function expression

circle.yml

@@ -8,7 +8,7 @@ macBuildFilters: &macBuildFilters
     branches:
       only:
         - develop
-        - try-new-electron-sign
+        - investigate-spec-on-mac
 
 defaults: &defaults
   parallelism: 1
@@ -325,6 +325,17 @@ jobs:
           command: yarn type-check --ignore-progress
       - store-npm-logs
 
+  build-system-unit-tests:
+    <<: *defaults
+    parallelism: 1
+    steps:
+      - attach_workspace:
+          at: ~/
+      # make sure mocha runs
+      - run: yarn test-mocha
+      # test binary build code
+      - run: yarn test-scripts
+
   "server-unit-tests":
     <<: *defaults
     parallelism: 2
@@ -1166,6 +1177,9 @@ linux-workflow: &linux-workflow
     - cli-visual-tests:
         requires:
           - build
+    - build-system-unit-tests:
+        requires:
+          - build
     - unit-tests:
         requires:
           - build
@@ -1403,7 +1417,14 @@ mac-workflow: &mac-workflow
         requires:
           - Mac build
 
-    # maybe run unit tests?
+    - build-system-unit-tests:
+        name: Mac build system unit tests
+        executor: mac
+        requires:
+          - Mac build
+        <<: *macBuildFilters
+
+    # maybe run all unit tests?
 
     - build-npm-package:
         name: Mac NPM package

scripts/unit/binary/util/packages-spec.js

@@ -1,3 +1,4 @@
+/* global sinon */
 const os = require('os')
 const _ = require('lodash')
 const path = require('path')
@@ -5,6 +6,7 @@ const proxyquire = require('proxyquire')
 const mockfs = require('mock-fs')
 const _snapshot = require('snap-shot-it')
 const chai = require('chai')
+const debug = require('debug')('test')
 
 chai.use(require('chai-as-promised'))
 
@@ -26,6 +28,8 @@ const snapshot = (...args) => {
 
 describe('packages', () => {
   it('can copy files from package.json', async () => {
+    sinon.stub(os, 'tmpdir').returns('/tmp')
+
     mockfs({
       'packages': {
         'coffee': {
@@ -77,7 +81,12 @@ describe('packages', () => {
 })
 
 describe('transformRequires', () => {
-  it('can find and replace symlink requires', async () => {
+  it('can find and replace symlink requires', async function () {
+    // these tests really refuse to work on Mac, so for now run it only on Linux
+    if (os.platform() !== 'linux') {
+      return this.skip()
+    }
+
     const buildRoot = 'build/linux/Cypress/resources/app'
 
     mockfs({
@@ -101,12 +110,22 @@ describe('transformRequires', () => {
     // should return number of transformed requires
     await expect(transformRequires(buildRoot)).to.eventually.eq(2)
 
-    // console.log(getFs())
+    const files = getFs()
 
-    snapshot(getFs())
+    if (debug.enabled) {
+      debug('returned file system')
+      /* eslint-disable-next-line no-console */
+      console.error(files)
+    }
+
+    snapshot(files)
   })
 
-  it('can find and replace symlink requires on win32', async () => {
+  it('can find and replace symlink requires on win32', async function () {
+    if (os.platform() !== 'linux') {
+      return this.skip()
+    }
+
     const { transformRequires } = proxyquire('../../../binary/util/transform-requires', { path: path.win32 })
     const buildRoot = 'build/linux/Cypress/resources/app'