fix(fs): wrap fs methods in try

This handles throwing better than `resolve`

src/commands/registration/cwd.js

@@ -7,7 +7,7 @@ module.exports = {
     if (!this.fs) return this.reply(550, 'File system not instantiated');
     if (!this.fs.chdir) return this.reply(402, 'Not supported by file system');
 
-    return Promise.resolve(this.fs.chdir(command.arg))
+    return Promise.try(() => this.fs.chdir(command.arg))
     .then(cwd => {
       const path = cwd ? `"${escapePath(cwd)}"` : undefined;
       return this.reply(250, path);

src/commands/registration/dele.js

@@ -6,7 +6,7 @@ module.exports = {
     if (!this.fs) return this.reply(550, 'File system not instantiated');
     if (!this.fs.delete) return this.reply(402, 'Not supported by file system');
 
-    return Promise.resolve(this.fs.delete(command.arg))
+    return Promise.try(() => this.fs.delete(command.arg))
     .then(() => {
       return this.reply(250);
     })

src/commands/registration/list.js

@@ -16,8 +16,8 @@ module.exports = {
     const path = command.arg || '.';
     return this.connector.waitForConnection()
     .tap(() => this.commandSocket.pause())
-    .then(() => Promise.resolve(this.fs.get(path)))
-    .then(stat => stat.isDirectory() ? Promise.resolve(this.fs.list(path)) : [stat])
+    .then(() => Promise.try(() => this.fs.get(path)))
+    .then(stat => stat.isDirectory() ? Promise.try(() => this.fs.list(path)) : [stat])
     .then(files => {
       const getFileMessage = file => {
         if (simple) return file.name;

src/commands/registration/mdtm.js

@@ -7,7 +7,7 @@ module.exports = {
     if (!this.fs) return this.reply(550, 'File system not instantiated');
     if (!this.fs.get) return this.reply(402, 'Not supported by file system');
 
-    return Promise.resolve(this.fs.get(command.arg))
+    return Promise.try(() => this.fs.get(command.arg))
     .then(fileStat => {
       const modificationTime = moment.utc(fileStat.mtime).format('YYYYMMDDHHmmss.SSS');
       return this.reply(213, modificationTime);

src/commands/registration/mkd.js

@@ -7,7 +7,7 @@ module.exports = {
     if (!this.fs) return this.reply(550, 'File system not instantiated');
     if (!this.fs.mkdir) return this.reply(402, 'Not supported by file system');
 
-    return Promise.resolve(this.fs.mkdir(command.arg))
+    return Promise.try(() => this.fs.mkdir(command.arg))
     .then(dir => {
       const path = dir ? `"${escapePath(dir)}"` : undefined;
       return this.reply(257, path);

src/commands/registration/pwd.js

@@ -7,7 +7,7 @@ module.exports = {
     if (!this.fs) return this.reply(550, 'File system not instantiated');
     if (!this.fs.currentDirectory) return this.reply(402, 'Not supported by file system');
 
-    return Promise.resolve(this.fs.currentDirectory())
+    return Promise.try(() => this.fs.currentDirectory())
     .then(cwd => {
       const path = cwd ? `"${escapePath(cwd)}"` : undefined;
       return this.reply(257, path);

src/commands/registration/retr.js

@@ -10,7 +10,7 @@ module.exports = {
 
     return this.connector.waitForConnection()
     .tap(() => this.commandSocket.pause())
-    .then(() => Promise.resolve(this.fs.read(filePath, {start: this.restByteCount})))
+    .then(() => Promise.try(() => this.fs.read(filePath, {start: this.restByteCount})))
     .then(stream => {
       const destroyConnection = (connection, reject) => err => {
         if (connection) connection.destroy(err);

src/commands/registration/rnfr.js

@@ -7,7 +7,7 @@ module.exports = {
     if (!this.fs.get) return this.reply(402, 'Not supported by file system');
 
     const fileName = command.arg;
-    return Promise.resolve(this.fs.get(fileName))
+    return Promise.try(() => this.fs.get(fileName))
     .then(() => {
       this.renameFrom = fileName;
       return this.reply(350);

src/commands/registration/rnto.js

@@ -11,7 +11,7 @@ module.exports = {
     const from = this.renameFrom;
     const to = command.arg;
 
-    return Promise.resolve(this.fs.rename(from, to))
+    return Promise.try(() => this.fs.rename(from, to))
     .then(() => {
       return this.reply(250);
     })

src/commands/registration/site/chmod.js

@@ -6,7 +6,7 @@ module.exports = function ({log, command} = {}) {
 
   const [mode, ...fileNameParts] = command.arg.split(' ');
   const fileName = fileNameParts.join(' ');
-  return Promise.resolve(this.fs.chmod(fileName, parseInt(mode, 8)))
+  return Promise.try(() => this.fs.chmod(fileName, parseInt(mode, 8)))
   .then(() => {
     return this.reply(200);
   })

src/commands/registration/size.js

@@ -6,7 +6,7 @@ module.exports = {
     if (!this.fs) return this.reply(550, 'File system not instantiated');
     if (!this.fs.get) return this.reply(402, 'Not supported by file system');
 
-    return Promise.resolve(this.fs.get(command.arg))
+    return Promise.try(() => this.fs.get(command.arg))
     .then(fileStat => {
       return this.reply(213, {message: fileStat.size});
     })

src/commands/registration/stat.js

@@ -11,12 +11,12 @@ module.exports = {
       if (!this.fs) return this.reply(550, 'File system not instantiated');
       if (!this.fs.get) return this.reply(402, 'Not supported by file system');
 
-      return Promise.resolve(this.fs.get(path))
+      return Promise.try(() => this.fs.get(path))
       .then(stat => {
         if (stat.isDirectory()) {
           if (!this.fs.list) return this.reply(402, 'Not supported by file system');
 
-          return Promise.resolve(this.fs.list(path))
+          return Promise.try(() => this.fs.list(path))
           .then(stats => [213, stats]);
         }
         return [212, [stat]];

src/commands/registration/stor.js

@@ -11,7 +11,7 @@ module.exports = {
 
     return this.connector.waitForConnection()
     .tap(() => this.commandSocket.pause())
-    .then(() => Promise.resolve(this.fs.write(fileName, {append, start: this.restByteCount})))
+    .then(() => Promise.try(() => this.fs.write(fileName, {append, start: this.restByteCount})))
     .then(stream => {
       const destroyConnection = (connection, reject) => err => {
         if (connection) connection.destroy(err);

src/commands/registration/stou.js

@@ -8,11 +8,9 @@ module.exports = {
     if (!this.fs.get || !this.fs.getUniqueName) return this.reply(402, 'Not supported by file system');
 
     const fileName = args.command.arg;
-    return Promise.try(() => {
-      return Promise.resolve(this.fs.get(fileName))
-      .then(() => Promise.resolve(this.fs.getUniqueName()))
-      .catch(() => Promise.resolve(fileName));
-    })
+    return Promise.try(() => this.fs.get(fileName))
+    .then(() => Promise.try(() => this.fs.getUniqueName()))
+    .catch(() => fileName)
     .then(name => {
       args.command.arg = name;
       return stor.call(this, args);

test/fs.spec.js

@@ -1,7 +1,9 @@
 const {expect} = require('chai');
 const nodePath = require('path');
+const Promise = require('bluebird');
 
 const FileSystem = require('../src/fs');
+const errors = require('../src/errors');
 
 describe('FileSystem', function () {
   let fs;
@@ -13,6 +15,25 @@ describe('FileSystem', function () {
     });
   });
 
+  describe('extend', function () {
+    class FileSystemOV extends FileSystem {
+      chdir() {
+        throw new errors.FileSystemError('Not a valid directory');
+      }
+    }
+    let ovFs;
+    before(function () {
+      ovFs = new FileSystemOV({});
+    });
+
+    it('handles error', function () {
+      return Promise.try(() => ovFs.chdir())
+      .catch(err => {
+        expect(err).to.be.instanceof(errors.FileSystemError);
+      });
+    });
+  });
+
   describe('#_resolvePath', function () {
     it('gets correct relative path', function () {
       const result = fs._resolvePath();

test/index.spec.js

@@ -385,7 +385,7 @@ describe('Integration', function () {
     runFileSystemTests('binary');
   });
 
-  describe.skip('#EXPLICIT', function () {
+  describe('#EXPLICIT', function () {
     before(() => {
       return server.close()
       .then(() => startServer('ftp://127.0.0.1:8880', {