refactor: use fs-extra instead of ncp and rimraf

fs-extra has promised based APIs, hence use it instead of promisifying
ncp and rimraf.

Author: vmx

package.json

@@ -34,13 +34,11 @@
     "chai": "^4.2.0",
     "cids": "~0.5.7",
     "dirty-chai": "^2.0.1",
+    "fs-extra": "^8.0.1",
     "ipfs-block": "~0.8.0",
     "ipfs-repo": "~0.27.0",
     "lodash": "^4.17.11",
-    "multihashing-async": "~0.7.0",
-    "ncp": "^2.0.0",
-    "promisify-es6": "^1.0.3",
-    "rimraf": "^2.6.3"
+    "multihashing-async": "~0.7.0"
   },
   "engines": {
     "node": ">=6.0.0",

test/node.js

@@ -1,9 +1,7 @@
 /* eslint-env mocha */
 'use strict'
 
-var promisify = require('promisify-es6')
-const ncp = require('ncp').ncp
-const rimraf = require('rimraf')
+const fs = require('fs-extra')
 const path = require('path')
 const IPFSRepo = require('ipfs-repo')
 
@@ -16,13 +14,13 @@ describe('IPFS Block Tests on Node.js', () => {
   const repo = new IPFSRepo(repoPath)
 
   before(async () => {
-    await promisify(ncp)(testRepoPath, repoPath)
+    await fs.copy(testRepoPath, repoPath)
     await repo.open()
   })
 
   after(async () => {
     await repo.close()
-    await promisify(rimraf)(repoPath)
+    await fs.remove(repoPath)
   })
 
   tests(repo)