fix(tests): Use proxyquire to mock fs object instead of mocking the f…

…ilesystem.

package.json

@@ -37,9 +37,9 @@
     "eslint": "2.4.0",
     "eslint-config-kentcdodds": "6.0.0",
     "ghooks": "1.0.3",
-    "mock-fs": "3.8.0",
     "npm-run-all": "1.5.3",
     "nyc": "6.1.1",
+    "proxyquire": "1.7.4",
     "semantic-release": "4.3.5",
     "validate-commit-msg": "2.4.0"
   },

test/index.js

@@ -1,19 +1,10 @@
-import mock from 'mock-fs'
+import proxyquire from 'proxyquire'
 import test from 'ava'
-import findNewRules from './index'
 
-test.before(() => {
-  mock({
-    './node_modules/eslint/lib/rules': {
-      'foo-rule.js': '',
-      'bar-rule.js': '',
-      'baz-thing.js': '',
-    },
-  })
-})
-
-test.after(() => {
-  mock.restore()
+const findNewRules = proxyquire('../index', {
+  fs: {
+    readdirSync: () => ['foo-rule.js', 'bar-rule.js', 'baz-thing.js'],
+  },
 })
 
 test('returns the difference between what it finds in eslint/lib/rules and the rules array it is passed', t => {
@@ -26,4 +17,3 @@ test('returns an empty array if there is no difference', t => {
   t.true(Array.isArray(missingRules))
   t.same(missingRules.length, 0)
 })
-