#8 add test cases for stat and lstat

src/fs.js

  * @return {RNFetchBlobFile}
  */
 function stat(path:string):Promise<RNFetchBlobFile> {
-
+  return new Promise((resolve, reject) => {
+    RNFetchBlob.stat(path, (err, stat) => {
+      if(err)
+        reject(err)
+      else
+        resolve(stat)
+    })
+  })
 }
 
 /**
  * @return {Promise}
  */
 function scanFile(paths:Array<string>, mimes: Array<string>):Promise {
-
+  return new Promise((resolve, reject) => {
+    RNFetchBlob.scanFile(path, (err) => {
+      if(err)
+        reject(err)
+      else
+        resolve()
+    })
+  })
 }
 
 function cp(path:string, dest:string):Promise<boolean> {
 }
 
 function lstat(path:string):Promise<Array<RNFetchBlobFile>> {
-
+  return new Promise((resolve, reject) => {
+    RNFetchBlob.lstat(path, (err, stat) => {
+      if(err)
+        reject(err)
+      else
+        resolve(stat)
+    })
+  })
 }
 
 function ls(path:string):Promise<Array<String>> {

test/react-native-testkit/lib/comparer.js

   isArray : (a, b) => Array.isArray(a),
   hasProperties : (a, b) => {
     let res = true
+    let c = 0
     for(let i in a) {
       let found = false
       for(let j in b) {
-        if(b[j] === i) {
+        c++
+        if(j === a[i]) {
           found = true
           break;
         }

test/test-fs.js

 describe('Get storage folders', (report, done) => {
   fs.getSystemDirs().then((resp) => {
     dirs = resp
+    console.log(dirs)
     report(
       <Assert key="system folders should exists" expect={resp} comparer={Comparer.exists} />,
       <Assert key="check properties"
-        expect={resp}
+        expect={['DocumentDir', 'CacheDir']}
         comparer={Comparer.hasProperties}
-        actual={['DocumentDir', 'CacheDir', 'DCIMDir', 'DownloadDir']}
+        actual={dirs}
       />,
       <Info key="System Folders">
         <Text>{`${JSON.stringify(dirs)}`}</Text>
   })
 })
 
+describe('stat and lstat test', (report, done) => {
+  let p = ''
+  let dirs = null
+  let file = null
+  fs.getSystemDirs().then((resp) => {
+    dirs = resp
+    p = dirs.DocumentDir + '/' + 'ls-stat-test' + Date.now()
+    return fs.lstat(dirs.DocumentDir)
+  })
+  // stat a folder
+  .then((stat) => {
+    report(
+      <Assert key="result should be an array"
+        expect={true}
+        actual={Array.isArray(stat)}/>)
+    file = stat[0].path
+    return fs.stat(file)
+  })
+  .then((stat) => {
+    console.log(stat)
+    report(
+      <Assert key="should have properties"
+        expect={['size', 'type', 'lastModified', 'filename', 'path']}
+        comparer={Comparer.hasProperties}
+        actual={stat}/>)
+    done()
+  })
+
+})
+
 function getASCIIArray(str) {
   let r = []
   for(let i=0;i<str.length;i++) {