diff --git a/src/connector/passive.js b/src/connector/passive.js
index 36677e36..f191f21a 100644
--- a/src/connector/passive.js
+++ b/src/connector/passive.js
@@ -89,7 +89,8 @@ class Passive extends Connector {
         this.server.options.pasv_range.split('-').map(v => v ? parseInt(v) : v) :
         [this.server.options.pasv_range];
       return findPort(min, max);
-    } else return undefined;
+    }
+    throw new errors.ConnectorError('Invalid pasv_range');
   }
 
 }
diff --git a/src/index.js b/src/index.js
index cecbb6d3..f1751546 100644
--- a/src/index.js
+++ b/src/index.js
@@ -95,7 +95,7 @@ class FtpServer {
 
   setupTLS(_tls) {
     if (!tls) return false;
-    return _.assign(_tls, {
+    return _.assign({}, _tls, {
       cert: _tls.cert ? fs.readFileSync(_tls.cert) : undefined,
       key: _tls.key ? fs.readFileSync(_tls.key) : undefined,
       ca: _tls.ca ? Array.isArray(_tls.ca) ? _tls.ca.map(_ca => fs.readFileSync(_ca)) : [fs.readFileSync(_tls.ca)] : undefined
diff --git a/test/commands/registration/abor.spec.js b/test/commands/registration/abor.spec.js
index 97aae3b4..2c3bdee5 100644
--- a/test/commands/registration/abor.spec.js
+++ b/test/commands/registration/abor.spec.js
@@ -25,29 +25,25 @@ describe(CMD, function () {
     sandbox.restore();
   });
 
-  it('// successful | no active connection', done => {
+  it('// successful | no active connection', () => {
     mockClient.connector.waitForConnection.restore();
     sandbox.stub(mockClient.connector, 'waitForConnection').rejects();
 
-    cmdFn()
+    return cmdFn()
     .then(() => {
       expect(mockClient.connector.waitForConnection.callCount).to.equal(1);
       expect(mockClient.connector.end.callCount).to.equal(0);
       expect(mockClient.reply.args[0][0]).to.equal(226);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('// successful | active connection', done => {
-    cmdFn()
+  it('// successful | active connection', () => {
+    return cmdFn()
     .then(() => {
       expect(mockClient.connector.waitForConnection.callCount).to.equal(1);
       expect(mockClient.connector.end.callCount).to.equal(1);
       expect(mockClient.reply.args[0][0]).to.equal(426);
       expect(mockClient.reply.args[1][0]).to.equal(226);
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/allo.spec.js b/test/commands/registration/allo.spec.js
index 8c9f1eff..0e59b95b 100644
--- a/test/commands/registration/allo.spec.js
+++ b/test/commands/registration/allo.spec.js
@@ -19,12 +19,10 @@ describe(CMD, function () {
     sandbox.restore();
   });
 
-  it('// successful', done => {
-    cmdFn()
+  it('// successful', () => {
+    return cmdFn()
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(202);
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/auth.spec.js b/test/commands/registration/auth.spec.js
index 798cdfcf..9401b062 100644
--- a/test/commands/registration/auth.spec.js
+++ b/test/commands/registration/auth.spec.js
@@ -22,31 +22,25 @@ describe(CMD, function () {
     sandbox.restore();
   });
 
-  it('TLS // supported', done => {
-    cmdFn({command: { arg: 'TLS', directive: CMD}})
+  it('TLS // supported', () => {
+    return cmdFn({command: { arg: 'TLS', directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(234);
       expect(mockClient.secure).to.equal(true);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('SSL // not supported', done => {
-    cmdFn({command: { arg: 'SSL', directive: CMD}})
+  it('SSL // not supported', () => {
+    return cmdFn({command: { arg: 'SSL', directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(504);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('bad // bad', done => {
-    cmdFn({command: { arg: 'bad', directive: CMD}})
+  it('bad // bad', () => {
+    return cmdFn({command: { arg: 'bad', directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(504);
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/cdup.spec.js b/test/commands/registration/cdup.spec.js
index 87205aea..1b5a12fe 100644
--- a/test/commands/registration/cdup.spec.js
+++ b/test/commands/registration/cdup.spec.js
@@ -25,13 +25,11 @@ describe(CMD, function () {
     sandbox.restore();
   });
 
-  it('.. // successful', done => {
-    cmdFn({log, command: {directive: CMD}})
+  it('.. // successful', () => {
+    return cmdFn({log, command: {directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(250);
       expect(mockClient.fs.chdir.args[0][0]).to.equal('..');
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/cwd.spec.js b/test/commands/registration/cwd.spec.js
index 6ed6d2b3..73ed1233 100644
--- a/test/commands/registration/cwd.spec.js
+++ b/test/commands/registration/cwd.spec.js
@@ -23,63 +23,56 @@ describe(CMD, function () {
   });
 
   describe('// check', function () {
-    it('fails on no fs', done => {
+    it('fails on no fs', () => {
       const badMockClient = { reply: () => {} };
       const badCmdFn = require(`../../../src/commands/registration/${CMD.toLowerCase()}`).handler.bind(badMockClient);
       sandbox.stub(badMockClient, 'reply').resolves();
-      badCmdFn()
+
+      return badCmdFn()
       .then(() => {
         expect(badMockClient.reply.args[0][0]).to.equal(550);
-        done();
-      })
-      .catch(done);
+      });
     });
 
-    it('fails on no fs chdir command', done => {
+    it('fails on no fs chdir command', () => {
       const badMockClient = { reply: () => {}, fs: {} };
       const badCmdFn = require(`../../../src/commands/registration/${CMD.toLowerCase()}`).handler.bind(badMockClient);
       sandbox.stub(badMockClient, 'reply').resolves();
-      badCmdFn()
+
+      return badCmdFn()
       .then(() => {
         expect(badMockClient.reply.args[0][0]).to.equal(402);
-        done();
-      })
-      .catch(done);
+      });
     });
   });
 
-  it('test // successful', done => {
-    cmdFn({log, command: { arg: 'test', directive: CMD}})
+  it('test // successful', () => {
+    return cmdFn({log, command: { arg: 'test', directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(250);
       expect(mockClient.fs.chdir.args[0][0]).to.equal('test');
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('test // successful', done => {
+  it('test // successful', () => {
     mockClient.fs.chdir.restore();
     sandbox.stub(mockClient.fs, 'chdir').resolves('/test');
-    cmdFn({log, command: { arg: 'test', directive: CMD}})
+
+    return cmdFn({log, command: { arg: 'test', directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(250);
       expect(mockClient.fs.chdir.args[0][0]).to.equal('test');
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('bad // unsuccessful', done => {
+  it('bad // unsuccessful', () => {
     mockClient.fs.chdir.restore();
     sandbox.stub(mockClient.fs, 'chdir').rejects(new Error('Bad'));
 
-    cmdFn({log, command: { arg: 'bad', directive: CMD}})
+    return cmdFn({log, command: { arg: 'bad', directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(550);
       expect(mockClient.fs.chdir.args[0][0]).to.equal('bad');
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/dele.spec.js b/test/commands/registration/dele.spec.js
index 2317f868..0a4130f9 100644
--- a/test/commands/registration/dele.spec.js
+++ b/test/commands/registration/dele.spec.js
@@ -23,51 +23,45 @@ describe(CMD, function () {
   });
 
   describe('// check', function () {
-    it('fails on no fs', done => {
+    it('fails on no fs', () => {
       const badMockClient = { reply: () => {} };
       const badCmdFn = require(`../../../src/commands/registration/${CMD.toLowerCase()}`).handler.bind(badMockClient);
       sandbox.stub(badMockClient, 'reply').resolves();
-      badCmdFn()
+
+      return badCmdFn()
       .then(() => {
         expect(badMockClient.reply.args[0][0]).to.equal(550);
-        done();
-      })
-      .catch(done);
+      });
     });
 
-    it('fails on no fs delete command', done => {
+    it('fails on no fs delete command', () => {
       const badMockClient = { reply: () => {}, fs: {} };
       const badCmdFn = require(`../../../src/commands/registration/${CMD.toLowerCase()}`).handler.bind(badMockClient);
       sandbox.stub(badMockClient, 'reply').resolves();
-      badCmdFn()
+
+      return badCmdFn()
       .then(() => {
         expect(badMockClient.reply.args[0][0]).to.equal(402);
-        done();
-      })
-      .catch(done);
+      });
     });
   });
 
-  it('test // successful', done => {
-    cmdFn({log, command: { arg: 'test', directive: CMD}})
+  it('test // successful', () => {
+    return cmdFn({log, command: { arg: 'test', directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(250);
       expect(mockClient.fs.delete.args[0][0]).to.equal('test');
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('bad // unsuccessful', done => {
+  it('bad // unsuccessful', () => {
     mockClient.fs.delete.restore();
     sandbox.stub(mockClient.fs, 'delete').rejects(new Error('Bad'));
 
-    cmdFn({log, command: { arg: 'bad', directive: CMD}})
+    return cmdFn({log, command: { arg: 'bad', directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(550);
       expect(mockClient.fs.delete.args[0][0]).to.equal('bad');
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/help.spec.js b/test/commands/registration/help.spec.js
index 061a10a3..2e83e3a7 100644
--- a/test/commands/registration/help.spec.js
+++ b/test/commands/registration/help.spec.js
@@ -19,39 +19,31 @@ describe(CMD, function () {
     sandbox.restore();
   });
 
-  it('// successful', done => {
-    cmdFn({command: { directive: CMD }})
+  it('// successful', () => {
+    return cmdFn({command: { directive: CMD }})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(211);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('help // successful', done => {
-    cmdFn({command: { arg: 'help', directive: CMD}})
+  it('help // successful', () => {
+    return cmdFn({command: { arg: 'help', directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(214);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('help // successful', done => {
-    cmdFn({command: { arg: 'allo', directive: CMD}})
+  it('allo // successful', () => {
+    return cmdFn({command: { arg: 'allo', directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(214);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('bad // unsuccessful', done => {
-    cmdFn({command: { arg: 'bad', directive: CMD}})
+  it('bad // unsuccessful', () => {
+    return cmdFn({command: { arg: 'bad', directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(502);
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/list.spec.js b/test/commands/registration/list.spec.js
index fc1a79dc..9da7f99f 100644
--- a/test/commands/registration/list.spec.js
+++ b/test/commands/registration/list.spec.js
@@ -87,33 +87,31 @@ describe(CMD, function () {
   });
 
   describe('// check', function () {
-    it('fails on no fs', done => {
+    it('fails on no fs', () => {
       const badMockClient = { reply: () => {} };
       const badCmdFn = require(`../../../src/commands/registration/${CMD.toLowerCase()}`).handler.bind(badMockClient);
       sandbox.stub(badMockClient, 'reply').resolves();
-      badCmdFn()
+
+      return badCmdFn()
       .then(() => {
         expect(badMockClient.reply.args[0][0]).to.equal(550);
-        done();
-      })
-      .catch(done);
+      });
     });
 
-    it('fails on no fs list command', done => {
+    it('fails on no fs list command', () => {
       const badMockClient = { reply: () => {}, fs: {} };
       const badCmdFn = require(`../../../src/commands/registration/${CMD.toLowerCase()}`).handler.bind(badMockClient);
       sandbox.stub(badMockClient, 'reply').resolves();
-      badCmdFn()
+
+      return badCmdFn()
       .then(() => {
         expect(badMockClient.reply.args[0][0]).to.equal(402);
-        done();
-      })
-      .catch(done);
+      });
     });
   });
 
-  it('. // successful', done => {
-    cmdFn({log, command: {directive: CMD}})
+  it('. // successful', () => {
+    return cmdFn({log, command: {directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(150);
       expect(mockClient.reply.args[1].length).to.equal(3);
@@ -121,12 +119,10 @@ describe(CMD, function () {
       expect(mockClient.reply.args[1][1]).to.have.property('message');
       expect(mockClient.reply.args[1][1]).to.have.property('socket');
       expect(mockClient.reply.args[2][0]).to.equal(226);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('testfile.txt // successful', done => {
+  it('testfile.txt // successful', () => {
     mockClient.fs.get.restore();
     sandbox.stub(mockClient.fs, 'get').resolves({
       name: 'testfile.txt',
@@ -147,7 +143,7 @@ describe(CMD, function () {
       isDirectory: () => false
     });
 
-    cmdFn({log, command: {directive: CMD, arg: 'testfile.txt'}})
+    return cmdFn({log, command: {directive: CMD, arg: 'testfile.txt'}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(150);
       expect(mockClient.reply.args[1].length).to.equal(2);
@@ -155,31 +151,25 @@ describe(CMD, function () {
       expect(mockClient.reply.args[1][1]).to.have.property('message');
       expect(mockClient.reply.args[1][1]).to.have.property('socket');
       expect(mockClient.reply.args[2][0]).to.equal(226);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('. // unsuccessful', done => {
+  it('. // unsuccessful', () => {
     mockClient.fs.list.restore();
     sandbox.stub(mockClient.fs, 'list').rejects(new Error());
 
-    cmdFn({log, command: {directive: CMD}})
+    return cmdFn({log, command: {directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(451);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('. // unsuccessful (timeout)', done => {
+  it('. // unsuccessful (timeout)', () => {
     sandbox.stub(mockClient.connector, 'waitForConnection').returns(when.reject(new when.TimeoutError()));
 
-    cmdFn({log, command: {directive: CMD}})
+    return cmdFn({log, command: {directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(425);
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/mdtm.spec.js b/test/commands/registration/mdtm.spec.js
index 431734a3..a7ef52f4 100644
--- a/test/commands/registration/mdtm.spec.js
+++ b/test/commands/registration/mdtm.spec.js
@@ -23,50 +23,44 @@ describe(CMD, function () {
   });
 
   describe('// check', function () {
-    it('fails on no fs', done => {
+    it('fails on no fs', () => {
       const badMockClient = { reply: () => {} };
       const badCmdFn = require(`../../../src/commands/registration/${CMD.toLowerCase()}`).handler.bind(badMockClient);
       sandbox.stub(badMockClient, 'reply').resolves();
-      badCmdFn()
+
+      return badCmdFn()
       .then(() => {
         expect(badMockClient.reply.args[0][0]).to.equal(550);
-        done();
-      })
-      .catch(done);
+      });
     });
 
-    it('fails on no fs get command', done => {
+    it('fails on no fs get command', () => {
       const badMockClient = { reply: () => {}, fs: {} };
       const badCmdFn = require(`../../../src/commands/registration/${CMD.toLowerCase()}`).handler.bind(badMockClient);
       sandbox.stub(badMockClient, 'reply').resolves();
-      badCmdFn()
+
+      return badCmdFn()
       .then(() => {
         expect(badMockClient.reply.args[0][0]).to.equal(402);
-        done();
-      })
-      .catch(done);
+      });
     });
   });
 
-  it('. // successful', done => {
-    cmdFn({log, command: {directive: CMD}})
+  it('. // successful', () => {
+    return cmdFn({log, command: {directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(213);
       //expect(mockClient.reply.args[0][1]).to.equal('20111010172411.000');
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('. // unsuccessful', done => {
+  it('. // unsuccessful', () => {
     mockClient.fs.get.restore();
     sandbox.stub(mockClient.fs, 'get').rejects(new Error());
 
-    cmdFn({log, command: {directive: CMD}})
+    return cmdFn({log, command: {directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(550);
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/mkd.spec.js b/test/commands/registration/mkd.spec.js
index 5375e3ac..6849498a 100644
--- a/test/commands/registration/mkd.spec.js
+++ b/test/commands/registration/mkd.spec.js
@@ -23,63 +23,56 @@ describe(CMD, function () {
   });
 
   describe('// check', function () {
-    it('fails on no fs', done => {
+    it('fails on no fs', () => {
       const badMockClient = { reply: () => {} };
       const badCmdFn = require(`../../../src/commands/registration/${CMD.toLowerCase()}`).handler.bind(badMockClient);
       sandbox.stub(badMockClient, 'reply').resolves();
-      badCmdFn()
+
+      return badCmdFn()
       .then(() => {
         expect(badMockClient.reply.args[0][0]).to.equal(550);
-        done();
-      })
-      .catch(done);
+      });
     });
 
-    it('fails on no fs mkdir command', done => {
+    it('fails on no fs mkdir command', () => {
       const badMockClient = { reply: () => {}, fs: {} };
       const badCmdFn = require(`../../../src/commands/registration/${CMD.toLowerCase()}`).handler.bind(badMockClient);
       sandbox.stub(badMockClient, 'reply').resolves();
-      badCmdFn()
+
+      return badCmdFn()
       .then(() => {
         expect(badMockClient.reply.args[0][0]).to.equal(402);
-        done();
-      })
-      .catch(done);
+      });
     });
   });
 
-  it('test // successful', done => {
-    cmdFn({log, command: {arg: 'test', directive: CMD}})
+  it('test // successful', () => {
+    return cmdFn({log, command: {arg: 'test', directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(257);
       expect(mockClient.fs.mkdir.args[0][0]).to.equal('test');
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('test // successful', done => {
+  it('test // successful', () => {
     mockClient.fs.mkdir.restore();
     sandbox.stub(mockClient.fs, 'mkdir').resolves('test');
-    cmdFn({log, command: {arg: 'test', directive: CMD}})
+
+    return cmdFn({log, command: {arg: 'test', directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(257);
       expect(mockClient.fs.mkdir.args[0][0]).to.equal('test');
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('bad // unsuccessful', done => {
+  it('bad // unsuccessful', () => {
     mockClient.fs.mkdir.restore();
     sandbox.stub(mockClient.fs, 'mkdir').rejects(new Error('Bad'));
 
-    cmdFn({log, command: {arg: 'bad', directive: CMD}})
+    return cmdFn({log, command: {arg: 'bad', directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(550);
       expect(mockClient.fs.mkdir.args[0][0]).to.equal('bad');
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/mode.spec.js b/test/commands/registration/mode.spec.js
index 4ee7e292..3296dfa5 100644
--- a/test/commands/registration/mode.spec.js
+++ b/test/commands/registration/mode.spec.js
@@ -19,21 +19,17 @@ describe(CMD, function () {
     sandbox.restore();
   });
 
-  it('S // successful', done => {
-    cmdFn({command: {arg: 'S'}})
+  it('S // successful', () => {
+    return cmdFn({command: {arg: 'S'}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(200);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('Q // unsuccessful', done => {
-    cmdFn({command: {arg: 'Q'}})
+  it('Q // unsuccessful', () => {
+    return cmdFn({command: {arg: 'Q'}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(504);
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/nlst.spec.js b/test/commands/registration/nlst.spec.js
index b3907a97..812c7dd8 100644
--- a/test/commands/registration/nlst.spec.js
+++ b/test/commands/registration/nlst.spec.js
@@ -86,8 +86,8 @@ describe(CMD, function () {
     sandbox.restore();
   });
 
-  it('. // successful', done => {
-    cmdFn({log, command: {directive: CMD}})
+  it('. // successful', () => {
+    return cmdFn({log, command: {directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(150);
       expect(mockClient.reply.args[1].length).to.equal(3);
@@ -95,12 +95,10 @@ describe(CMD, function () {
       expect(mockClient.reply.args[1][1]).to.have.property('message');
       expect(mockClient.reply.args[1][1]).to.have.property('socket');
       expect(mockClient.reply.args[2][0]).to.equal(226);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('testfile.txt // successful', done => {
+  it('testfile.txt // successful', () => {
     mockClient.fs.get.restore();
     sandbox.stub(mockClient.fs, 'get').resolves({
       name: 'testfile.txt',
@@ -121,7 +119,7 @@ describe(CMD, function () {
       isDirectory: () => false
     });
 
-    cmdFn({log, command: {directive: CMD, arg: 'testfile.txt'}})
+    return cmdFn({log, command: {directive: CMD, arg: 'testfile.txt'}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(150);
       expect(mockClient.reply.args[1].length).to.equal(2);
@@ -129,8 +127,6 @@ describe(CMD, function () {
       expect(mockClient.reply.args[1][1]).to.have.property('message');
       expect(mockClient.reply.args[1][1]).to.have.property('socket');
       expect(mockClient.reply.args[2][0]).to.equal(226);
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/noop.spec.js b/test/commands/registration/noop.spec.js
index 19f1c682..152a082e 100644
--- a/test/commands/registration/noop.spec.js
+++ b/test/commands/registration/noop.spec.js
@@ -19,12 +19,10 @@ describe(CMD, function () {
     sandbox.restore();
   });
 
-  it('// successful', done => {
-    cmdFn()
+  it('// successful', () => {
+    return cmdFn()
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(200);
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/opts.spec.js b/test/commands/registration/opts.spec.js
index e3efba02..6b60dd2e 100644
--- a/test/commands/registration/opts.spec.js
+++ b/test/commands/registration/opts.spec.js
@@ -19,12 +19,10 @@ describe(CMD, function () {
     sandbox.restore();
   });
 
-  it('// successful', done => {
-    cmdFn()
+  it('// successful', () => {
+    return cmdFn()
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(501);
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/pass.spec.js b/test/commands/registration/pass.spec.js
index af97ed1c..b1d53230 100644
--- a/test/commands/registration/pass.spec.js
+++ b/test/commands/registration/pass.spec.js
@@ -24,61 +24,51 @@ describe(CMD, function () {
     sandbox.restore();
   });
 
-  it('pass // successful', done => {
-    cmdFn({log, command: {arg: 'pass', directive: CMD}})
+  it('pass // successful', () => {
+    return cmdFn({log, command: {arg: 'pass', directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(230);
       expect(mockClient.login.args[0]).to.eql(['anonymous', 'pass']);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('// successful (already authenticated)', done => {
+  it('// successful (already authenticated)', () => {
     mockClient.server.options.anonymous = true;
     mockClient.authenticated = true;
-    cmdFn({log, command: {directive: CMD}})
+    return cmdFn({log, command: {directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(202);
       expect(mockClient.login.callCount).to.equal(0);
       mockClient.server.options.anonymous = false;
       mockClient.authenticated = false;
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('bad // unsuccessful', done => {
+  it('bad // unsuccessful', () => {
     mockClient.login.restore();
     sandbox.stub(mockClient, 'login').rejects('bad');
 
-    cmdFn({log, command: {arg: 'bad', directive: CMD}})
+    return cmdFn({log, command: {arg: 'bad', directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(530);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('bad // unsuccessful', done => {
+  it('bad // unsuccessful', () => {
     mockClient.login.restore();
     sandbox.stub(mockClient, 'login').rejects({});
 
-    cmdFn({log, command: {arg: 'bad', directive: CMD}})
+    return cmdFn({log, command: {arg: 'bad', directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(530);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('bad // unsuccessful', done => {
+  it('bad // unsuccessful', () => {
     delete mockClient.username;
-    cmdFn({log, command: {arg: 'bad', directive: CMD}})
+    return cmdFn({log, command: {arg: 'bad', directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(503);
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/pbsz.spec.js b/test/commands/registration/pbsz.spec.js
index 1bd1d7b8..ce508269 100644
--- a/test/commands/registration/pbsz.spec.js
+++ b/test/commands/registration/pbsz.spec.js
@@ -20,38 +20,32 @@ describe(CMD, function () {
     sandbox.restore();
   });
 
-  it('// unsuccessful', done => {
-    cmdFn()
+  it('// unsuccessful', () => {
+    return cmdFn()
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(202);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('// successful', done => {
+  it('// successful', () => {
     mockClient.secure = true;
     mockClient.server._tls = {};
 
-    cmdFn({command: {arg: '0'}})
+    return cmdFn({command: {arg: '0'}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(200);
       expect(mockClient.bufferSize).to.equal(0);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('// successful', done => {
+  it('// successful', () => {
     mockClient.secure = true;
     mockClient.server._tls = {};
 
-    cmdFn({command: {arg: '10'}})
+    return cmdFn({command: {arg: '10'}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(200);
       expect(mockClient.bufferSize).to.equal(10);
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/port.spec.js b/test/commands/registration/port.spec.js
index 09d51d97..fb880d52 100644
--- a/test/commands/registration/port.spec.js
+++ b/test/commands/registration/port.spec.js
@@ -22,33 +22,27 @@ describe(CMD, function () {
     sandbox.restore();
   });
 
-  it('// unsuccessful | no argument', done => {
-    cmdFn()
+  it('// unsuccessful | no argument', () => {
+    return cmdFn()
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(425);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('// unsuccessful | invalid argument', done => {
-    cmdFn({ command: { arg: '1,2,3,4,5' } })
+  it('// unsuccessful | invalid argument', () => {
+    return cmdFn({ command: { arg: '1,2,3,4,5' } })
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(425);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('// successful', done => {
-    cmdFn({ command: { arg: '192,168,0,100,137,214' } })
+  it('// successful', () => {
+    return cmdFn({ command: { arg: '192,168,0,100,137,214' } })
     .then(() => {
       const [ip, port] = ActiveConnector.prototype.setupConnection.args[0];
       expect(mockClient.reply.args[0][0]).to.equal(200);
       expect(ip).to.equal('192.168.0.100');
       expect(port).to.equal(35286);
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/prot.spec.js b/test/commands/registration/prot.spec.js
index 97b93766..50cc5453 100644
--- a/test/commands/registration/prot.spec.js
+++ b/test/commands/registration/prot.spec.js
@@ -20,56 +20,46 @@ describe(CMD, function () {
     sandbox.restore();
   });
 
-  it('// unsuccessful', done => {
-    cmdFn()
+  it('// unsuccessful', () => {
+    return cmdFn()
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(202);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('// unsuccessful - no bufferSize', done => {
+  it('// unsuccessful - no bufferSize', () => {
     mockClient.server._tls = {};
     mockClient.secure = true;
 
-    cmdFn({command: {arg: 'P'}})
+    return cmdFn({command: {arg: 'P'}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(503);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('// successful', done => {
+  it('// successful', () => {
     mockClient.bufferSize = 0;
     mockClient.secure = true;
 
-    cmdFn({command: {arg: 'p'}})
+    return cmdFn({command: {arg: 'p'}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(200);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('// unsuccessful - unsupported', done => {
+  it('// unsuccessful - unsupported', () => {
     mockClient.secure = true;
-    cmdFn({command: {arg: 'C'}})
+    return cmdFn({command: {arg: 'C'}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(536);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('// unsuccessful - unknown', done => {
+  it('// unsuccessful - unknown', () => {
     mockClient.secure = true;
-    cmdFn({command: {arg: 'QQ'}})
+    return cmdFn({command: {arg: 'QQ'}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(504);
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/pwd.spec.js b/test/commands/registration/pwd.spec.js
index 2e64e68b..8f95126b 100644
--- a/test/commands/registration/pwd.spec.js
+++ b/test/commands/registration/pwd.spec.js
@@ -23,61 +23,53 @@ describe(CMD, function () {
   });
 
   describe('// check', function () {
-    it('fails on no fs', done => {
+    it('fails on no fs', () => {
       const badMockClient = { reply: () => {} };
       const badCmdFn = require(`../../../src/commands/registration/${CMD.toLowerCase()}`).handler.bind(badMockClient);
       sandbox.stub(badMockClient, 'reply').resolves();
-      badCmdFn()
+
+      return badCmdFn()
       .then(() => {
         expect(badMockClient.reply.args[0][0]).to.equal(550);
-        done();
-      })
-      .catch(done);
+      });
     });
 
-    it('fails on no fs currentDirectory command', done => {
+    it('fails on no fs currentDirectory command', () => {
       const badMockClient = { reply: () => {}, fs: {} };
       const badCmdFn = require(`../../../src/commands/registration/${CMD.toLowerCase()}`).handler.bind(badMockClient);
       sandbox.stub(badMockClient, 'reply').resolves();
-      badCmdFn()
+
+      return badCmdFn()
       .then(() => {
         expect(badMockClient.reply.args[0][0]).to.equal(402);
-        done();
-      })
-      .catch(done);
+      });
     });
   });
 
-  it('// successful', done => {
-    cmdFn({log, command: { arg: 'test', directive: CMD}})
+  it('// successful', () => {
+    return cmdFn({log, command: { arg: 'test', directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(257);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('// successful', done => {
+  it('// successful', () => {
     mockClient.fs.currentDirectory.restore();
     sandbox.stub(mockClient.fs, 'currentDirectory').resolves('/test');
 
-    cmdFn({log, command: {arg: 'test', directive: CMD}})
+    return cmdFn({log, command: {arg: 'test', directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(257);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('// unsuccessful', done => {
+  it('// unsuccessful', () => {
     mockClient.fs.currentDirectory.restore();
     sandbox.stub(mockClient.fs, 'currentDirectory').rejects(new Error('Bad'));
 
-    cmdFn({log, command: {arg: 'bad', directive: CMD}})
+    return cmdFn({log, command: {arg: 'bad', directive: CMD}})
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(550);
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/quit.spec.js b/test/commands/registration/quit.spec.js
index e453aa52..a6a696fa 100644
--- a/test/commands/registration/quit.spec.js
+++ b/test/commands/registration/quit.spec.js
@@ -18,12 +18,10 @@ describe(CMD, function () {
     sandbox.restore();
   });
 
-  it('// successful', done => {
-    cmdFn()
+  it('// successful', () => {
+    return cmdFn()
     .then(() => {
       expect(mockClient.close.callCount).to.equal(1);
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/retr.spec.js b/test/commands/registration/retr.spec.js
new file mode 100644
index 00000000..ff22d801
--- /dev/null
+++ b/test/commands/registration/retr.spec.js
@@ -0,0 +1,75 @@
+const when = require('when');
+const bunyan = require('bunyan');
+const {expect} = require('chai');
+const sinon = require('sinon');
+
+const CMD = 'RETR';
+describe(CMD, function () {
+  let sandbox;
+  let log = bunyan.createLogger({name: CMD});
+  const mockClient = {
+    commandSocket: {
+      pause: () => {},
+      resume: () => {}
+    },
+    reply: () => when.resolve(),
+    connector: {
+      waitForConnection: () => when.resolve({
+        resume: () => {}
+      }),
+      end: () => {}
+    }
+  };
+  const cmdFn = require(`../../../src/commands/registration/${CMD.toLowerCase()}`).handler.bind(mockClient);
+
+  beforeEach(() => {
+    sandbox = sinon.sandbox.create();
+
+    mockClient.fs = {
+      read: () => {}
+    };
+
+    sandbox.spy(mockClient, 'reply');
+  });
+  afterEach(() => sandbox.restore());
+
+  it('// unsuccessful | no file system', () => {
+    delete mockClient.fs;
+
+    return cmdFn()
+    .then(() => {
+      expect(mockClient.reply.args[0][0]).to.equal(550);
+    });
+  });
+
+  it('// unsuccessful | file system does not have functions', () => {
+    mockClient.fs = {};
+
+    return cmdFn()
+    .then(() => {
+      expect(mockClient.reply.args[0][0]).to.equal(402);
+    });
+  });
+
+  it('// unsuccessful | connector times out', () => {
+    sandbox.stub(mockClient.connector, 'waitForConnection').callsFake(function () {
+      return when.reject(new when.TimeoutError());
+    });
+
+    return cmdFn({log, command: {arg: 'test.txt'} })
+    .then(() => {
+      expect(mockClient.reply.args[0][0]).to.equal(425);
+    });
+  });
+
+  it('// unsuccessful | connector errors out', () => {
+    sandbox.stub(mockClient.connector, 'waitForConnection').callsFake(function () {
+      return when.reject(new Error('test'));
+    });
+
+    return cmdFn({log, command: {arg: 'test.txt'} })
+    .then(() => {
+      expect(mockClient.reply.args[0][0]).to.equal(551);
+    });
+  });
+});
diff --git a/test/commands/registration/rnfr.spec.js b/test/commands/registration/rnfr.spec.js
index 0c51dc52..00ae371a 100644
--- a/test/commands/registration/rnfr.spec.js
+++ b/test/commands/registration/rnfr.spec.js
@@ -24,47 +24,39 @@ describe(CMD, function () {
     sandbox.restore();
   });
 
-  it('// unsuccessful | no file system', done => {
+  it('// unsuccessful | no file system', () => {
     delete mockClient.fs;
 
-    cmdFn()
+    return cmdFn()
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(550);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('// unsuccessful | file system does not have functions', done => {
+  it('// unsuccessful | file system does not have functions', () => {
     mockClient.fs = {};
 
-    cmdFn()
+    return cmdFn()
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(402);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('test // unsuccessful | file get fails', done => {
+  it('test // unsuccessful | file get fails', () => {
     mockClient.fs.get.restore();
     sandbox.stub(mockClient.fs, 'get').rejects(new Error('test'));
 
-    cmdFn({ log: mockLog, command: { arg: 'test' } })
+    return cmdFn({ log: mockLog, command: { arg: 'test' } })
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(550);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('test // successful', done => {
-    cmdFn({ log: mockLog, command: { arg: 'test' } })
+  it('test // successful', () => {
+    return cmdFn({ log: mockLog, command: { arg: 'test' } })
     .then(() => {
       expect(mockClient.fs.get.args[0][0]).to.equal('test');
       expect(mockClient.reply.args[0][0]).to.equal(350);
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/rnto.spec.js b/test/commands/registration/rnto.spec.js
index 84aff483..bd569388 100644
--- a/test/commands/registration/rnto.spec.js
+++ b/test/commands/registration/rnto.spec.js
@@ -25,58 +25,48 @@ describe(CMD, function () {
     sandbox.restore();
   });
 
-  it('// unsuccessful | no renameFrom set', done => {
+  it('// unsuccessful | no renameFrom set', () => {
     delete mockClient.renameFrom;
 
-    cmdFn()
+    return cmdFn()
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(503);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('// unsuccessful | no file system', done => {
+  it('// unsuccessful | no file system', () => {
     delete mockClient.fs;
 
-    cmdFn()
+    return cmdFn()
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(550);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('// unsuccessful | file system does not have functions', done => {
+  it('// unsuccessful | file system does not have functions', () => {
     mockClient.fs = {};
 
-    cmdFn()
+    return cmdFn()
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(402);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('new // unsuccessful | rename fails', done => {
+  it('new // unsuccessful | rename fails', () => {
     mockClient.fs.rename.restore();
     sandbox.stub(mockClient.fs, 'rename').rejects(new Error('test'));
 
-    cmdFn({ log: mockLog, command: { arg: 'new' } })
+    return cmdFn({ log: mockLog, command: { arg: 'new' } })
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(550);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('new // successful', done => {
-    cmdFn({ command: { arg: 'new' } })
+  it('new // successful', () => {
+    return cmdFn({ command: { arg: 'new' } })
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(250);
       expect(mockClient.fs.rename.args[0]).to.eql(['test', 'new']);
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/size.spec.js b/test/commands/registration/size.spec.js
index 733c8d89..f692ca98 100644
--- a/test/commands/registration/size.spec.js
+++ b/test/commands/registration/size.spec.js
@@ -22,45 +22,37 @@ describe(CMD, function () {
     sandbox.restore();
   });
 
-  it('// unsuccessful | no file system', done => {
+  it('// unsuccessful | no file system', () => {
     delete mockClient.fs;
 
-    cmdFn()
+    return cmdFn()
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(550);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('// unsuccessful | file system does not have functions', done => {
+  it('// unsuccessful | file system does not have functions', () => {
     mockClient.fs = {};
 
-    cmdFn()
+    return cmdFn()
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(402);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('// unsuccessful | file get fails', done => {
+  it('// unsuccessful | file get fails', () => {
     sandbox.stub(mockClient.fs, 'get').rejects(new Error('test'));
 
-    cmdFn({ log: mockLog, command: { arg: 'test' } })
+    return cmdFn({ log: mockLog, command: { arg: 'test' } })
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(550);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('// successful', done => {
-    cmdFn({ command: { arg: 'test' } })
+  it('// successful', () => {
+    return cmdFn({ command: { arg: 'test' } })
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(213);
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/stat.spec.js b/test/commands/registration/stat.spec.js
index 5693f8bc..e69ef17e 100644
--- a/test/commands/registration/stat.spec.js
+++ b/test/commands/registration/stat.spec.js
@@ -23,49 +23,41 @@ describe(CMD, function () {
     sandbox.restore();
   });
 
-  it('// successful', done => {
-    cmdFn()
+  it('// successful', () => {
+    return cmdFn()
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(211);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('// unsuccessful | no file system', done => {
+  it('// unsuccessful | no file system', () => {
     delete mockClient.fs;
 
-    cmdFn({ command: { arg: 'test' } })
+    return cmdFn({ command: { arg: 'test' } })
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(550);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('// unsuccessful | file system does not have functions', done => {
+  it('// unsuccessful | file system does not have functions', () => {
     mockClient.fs = {};
 
-    cmdFn({ command: { arg: 'test' } })
+    return cmdFn({ command: { arg: 'test' } })
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(402);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('// unsuccessful | file get fails', done => {
+  it('// unsuccessful | file get fails', () => {
     sandbox.stub(mockClient.fs, 'get').rejects(new Error('test'));
 
-    cmdFn({ log: mockLog, command: { arg: 'test' } })
+    return cmdFn({ log: mockLog, command: { arg: 'test' } })
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(450);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('// successful | file', done => {
+  it('// successful | file', () => {
     sandbox.stub(mockClient.fs, 'get').returns({
       name: 'test_file',
       dev: 2114,
@@ -85,15 +77,13 @@ describe(CMD, function () {
       isDirectory: () => false
     });
 
-    cmdFn({ command: { arg: 'test' } })
+    return cmdFn({ command: { arg: 'test' } })
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(212);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('// successful | directory', done => {
+  it('// successful | directory', () => {
     sandbox.stub(mockClient.fs, 'list').returns([{
       name: 'test_file',
       dev: 2114,
@@ -132,11 +122,9 @@ describe(CMD, function () {
       isDirectory: () => true
     });
 
-    cmdFn({ command: { arg: 'test' } })
+    return cmdFn({ command: { arg: 'test' } })
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(213);
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/stor.spec.js b/test/commands/registration/stor.spec.js
new file mode 100644
index 00000000..e8c7df17
--- /dev/null
+++ b/test/commands/registration/stor.spec.js
@@ -0,0 +1,75 @@
+const when = require('when');
+const bunyan = require('bunyan');
+const {expect} = require('chai');
+const sinon = require('sinon');
+
+const CMD = 'STOR';
+describe(CMD, function () {
+  let sandbox;
+  let log = bunyan.createLogger({name: CMD});
+  const mockClient = {
+    commandSocket: {
+      pause: () => {},
+      resume: () => {}
+    },
+    reply: () => when.resolve(),
+    connector: {
+      waitForConnection: () => when.resolve({
+        resume: () => {}
+      }),
+      end: () => {}
+    }
+  };
+  const cmdFn = require(`../../../src/commands/registration/${CMD.toLowerCase()}`).handler.bind(mockClient);
+
+  beforeEach(() => {
+    sandbox = sinon.sandbox.create();
+
+    mockClient.fs = {
+      write: () => {}
+    };
+
+    sandbox.spy(mockClient, 'reply');
+  });
+  afterEach(() => sandbox.restore());
+
+  it('// unsuccessful | no file system', () => {
+    delete mockClient.fs;
+
+    return cmdFn()
+    .then(() => {
+      expect(mockClient.reply.args[0][0]).to.equal(550);
+    });
+  });
+
+  it('// unsuccessful | file system does not have functions', () => {
+    mockClient.fs = {};
+
+    return cmdFn()
+    .then(() => {
+      expect(mockClient.reply.args[0][0]).to.equal(402);
+    });
+  });
+
+  it('// unsuccessful | connector times out', () => {
+    sandbox.stub(mockClient.connector, 'waitForConnection').callsFake(function () {
+      return when.reject(new when.TimeoutError());
+    });
+
+    return cmdFn({log, command: {arg: 'test.txt'} })
+    .then(() => {
+      expect(mockClient.reply.args[0][0]).to.equal(425);
+    });
+  });
+
+  it('// unsuccessful | connector errors out', () => {
+    sandbox.stub(mockClient.connector, 'waitForConnection').callsFake(function () {
+      return when.reject(new Error('test'));
+    });
+
+    return cmdFn({log, command: {arg: 'test.txt'} })
+    .then(() => {
+      expect(mockClient.reply.args[0][0]).to.equal(550);
+    });
+  });
+});
diff --git a/test/commands/registration/stou.spec.js b/test/commands/registration/stou.spec.js
index 4337dc59..113b9a2b 100644
--- a/test/commands/registration/stou.spec.js
+++ b/test/commands/registration/stou.spec.js
@@ -30,54 +30,46 @@ describe(CMD, function () {
     sandbox.restore();
   });
 
-  it('// unsuccessful | no file system', done => {
+  it('// unsuccessful | no file system', () => {
     delete mockClient.fs;
 
-    cmdFn()
+    return cmdFn()
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(550);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('// unsuccessful | file system does not have functions', done => {
+  it('// unsuccessful | file system does not have functions', () => {
     mockClient.fs = {};
 
-    cmdFn()
+    return cmdFn()
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(402);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('// successful | given name is unique', done => {
+  it('// successful | given name is unique', () => {
     mockClient.fs.get.restore();
     sandbox.stub(mockClient.fs, 'get').rejects({});
 
-    cmdFn({ command: { arg: 'good' } })
+    return cmdFn({ command: { arg: 'good' } })
     .then(() => {
       const call = stor.handler.call.args[0][1];
       expect(call).to.have.property('command');
       expect(call.command).to.have.property('arg');
       expect(call.command.arg).to.eql('good');
       expect(mockClient.fs.getUniqueName.callCount).to.equal(0);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('// successful | generates unique name', done => {
-    cmdFn({ command: { arg: 'bad' } })
+  it('// successful | generates unique name', () => {
+    return cmdFn({ command: { arg: 'bad' } })
     .then(() => {
       const call = stor.handler.call.args[0][1];
       expect(call).to.have.property('command');
       expect(call.command).to.have.property('arg');
       expect(call.command.arg).to.eql('4');
       expect(mockClient.fs.getUniqueName.callCount).to.equal(1);
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/stru.spec.js b/test/commands/registration/stru.spec.js
index db553549..ebd12911 100644
--- a/test/commands/registration/stru.spec.js
+++ b/test/commands/registration/stru.spec.js
@@ -19,21 +19,17 @@ describe(CMD, function () {
     sandbox.restore();
   });
 
-  it('// successful', done => {
-    cmdFn({command: { arg: 'F' } })
+  it('// successful', () => {
+    return cmdFn({command: { arg: 'F' } })
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(200);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('// unsuccessful', done => {
-    cmdFn({command: { arg: 'X' } })
+  it('// unsuccessful', () => {
+    return cmdFn({command: { arg: 'X' } })
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(504);
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/syst.spec.js b/test/commands/registration/syst.spec.js
index 2caf763c..e7bde9bc 100644
--- a/test/commands/registration/syst.spec.js
+++ b/test/commands/registration/syst.spec.js
@@ -19,12 +19,10 @@ describe(CMD, function () {
     sandbox.restore();
   });
 
-  it('// successful', done => {
-    cmdFn()
+  it('// successful', () => {
+    return cmdFn()
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(215);
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/type.spec.js b/test/commands/registration/type.spec.js
index 6f60bb30..0f5541d2 100644
--- a/test/commands/registration/type.spec.js
+++ b/test/commands/registration/type.spec.js
@@ -20,43 +20,35 @@ describe(CMD, function () {
     sandbox.restore();
   });
 
-  it('A // successful', done => {
-    cmdFn({ command: { arg: 'A' } })
+  it('A // successful', () => {
+    return cmdFn({ command: { arg: 'A' } })
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(200);
       expect(mockClient.encoding).to.equal('utf8');
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('I // successful', done => {
-    cmdFn({ command: { arg: 'I' } })
+  it('I // successful', () => {
+    return cmdFn({ command: { arg: 'I' } })
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(200);
       expect(mockClient.encoding).to.equal('binary');
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('L // successful', done => {
-    cmdFn({ command: { arg: 'L' } })
+  it('L // successful', () => {
+    return cmdFn({ command: { arg: 'L' } })
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(200);
       expect(mockClient.encoding).to.equal('binary');
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('X // successful', done => {
-    cmdFn({ command: { arg: 'X' } })
+  it('X // successful', () => {
+    return cmdFn({ command: { arg: 'X' } })
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(501);
       expect(mockClient.encoding).to.equal(null);
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/commands/registration/user.spec.js b/test/commands/registration/user.spec.js
index 0662acfa..11dc3634 100644
--- a/test/commands/registration/user.spec.js
+++ b/test/commands/registration/user.spec.js
@@ -28,70 +28,80 @@ describe(CMD, function () {
     sandbox.restore();
   });
 
-  it('test // successful | prompt for password', done => {
-    cmdFn({ command: { arg: 'test' } })
+  it('test // successful | prompt for password', () => {
+    return cmdFn({ command: { arg: 'test' } })
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(331);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('test // successful | anonymous login', done => {
+  it('test // successful | anonymous login', () => {
     mockClient.server.options = {anonymous: true};
 
-    cmdFn({ command: { arg: 'anonymous' } })
+    return cmdFn({ command: { arg: 'anonymous' } })
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(230);
       expect(mockClient.login.callCount).to.equal(1);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('test // unsuccessful | no username provided', done => {
-    cmdFn({ command: { } })
+  it('test // unsuccessful | no username provided', () => {
+    return cmdFn({ command: { } })
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(501);
       expect(mockClient.login.callCount).to.equal(0);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('test // unsuccessful | already set username', done => {
+  it('test // unsuccessful | already set username', () => {
     mockClient.username = 'test';
 
-    cmdFn({ command: { arg: 'test' } })
+    return cmdFn({ command: { arg: 'test' } })
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(530);
       expect(mockClient.login.callCount).to.equal(0);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('test // successful | regular login if anonymous is true', done => {
+  it('test // successful | regular login if anonymous is true', () => {
     mockClient.server.options = {anonymous: true};
 
-    cmdFn({ log: mockLog, command: { arg: 'test' } })
+    return cmdFn({ log: mockLog, command: { arg: 'test' } })
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(331);
       expect(mockClient.login.callCount).to.equal(0);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('test // successful | anonymous login with set username', done => {
+  it('test // successful | anonymous login with set username', () => {
     mockClient.server.options = {anonymous: 'sillyrabbit'};
 
-    cmdFn({ log: mockLog, command: { arg: 'sillyrabbit' } })
+    return cmdFn({ log: mockLog, command: { arg: 'sillyrabbit' } })
     .then(() => {
       expect(mockClient.reply.args[0][0]).to.equal(230);
       expect(mockClient.login.callCount).to.equal(1);
-      done();
-    })
-    .catch(done);
+    });
+  });
+
+  it('test // unsuccessful | anonymous login fails', () => {
+    mockClient.server.options = {anonymous: true};
+    mockClient.login.restore();
+    sandbox.stub(mockClient, 'login').rejects(new Error('test'));
+
+    return cmdFn({ log: mockLog, command: { arg: 'anonymous' } })
+    .then(() => {
+      expect(mockClient.reply.args[0][0]).to.equal(530);
+      expect(mockClient.login.callCount).to.equal(1);
+    });
+  });
+
+  it('test // successful | does not login if already authenticated', () => {
+    mockClient.authenticated = true;
+
+    return cmdFn({ log: mockLog, command: { arg: 'sillyrabbit' } })
+    .then(() => {
+      expect(mockClient.reply.args[0][0]).to.equal(230);
+      expect(mockClient.login.callCount).to.equal(0);
+    });
   });
 });
diff --git a/test/connector/active.spec.js b/test/connector/active.spec.js
index 4fa2913b..b25a3e05 100644
--- a/test/connector/active.spec.js
+++ b/test/connector/active.spec.js
@@ -3,6 +3,7 @@ const {expect} = require('chai');
 const sinon = require('sinon');
 
 const net = require('net');
+const tls = require('tls');
 
 const ActiveConnector = require('../../src/connector/active');
 const findPort = require('../../src/helpers/find-port');
@@ -33,34 +34,49 @@ describe('Connector - Active //', function () {
     server.close(done);
   });
 
-  it('sets up a connection', function (done) {
-    active.setupConnection('127.0.0.1', PORT)
+  it('sets up a connection', function () {
+    return active.setupConnection('127.0.0.1', PORT)
     .then(() => {
       expect(active.dataSocket).to.exist;
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('destroys existing connection, then sets up a connection', function (done) {
+  it('destroys existing connection, then sets up a connection', function () {
     const destroyFnSpy = sandbox.spy(active.dataSocket, 'destroy');
 
-    active.setupConnection('127.0.0.1', PORT)
+    return active.setupConnection('127.0.0.1', PORT)
     .then(() => {
       expect(destroyFnSpy.callCount).to.equal(1);
       expect(active.dataSocket).to.exist;
-      done();
+    });
+  });
+
+  it('waits for connection', function () {
+    return active.setupConnection('127.0.0.1', PORT)
+    .then(() => {
+      expect(active.dataSocket).to.exist;
+      return active.waitForConnection();
     })
-    .catch(done);
+    .then(dataSocket => {
+      expect(dataSocket.connected).to.equal(true);
+      expect(dataSocket instanceof net.Socket).to.equal(true);
+      expect(dataSocket instanceof tls.TLSSocket).to.equal(false);
+    });
   });
 
-  it('waits for connection', function (done) {
-    active.setupConnection('127.0.0.1', PORT)
+  it('upgrades to a secure connection', function () {
+    mockConnection.secure = true;
+    mockConnection.server = { _tls: {} };
+
+    return active.setupConnection('127.0.0.1', PORT)
     .then(() => {
       expect(active.dataSocket).to.exist;
       return active.waitForConnection();
     })
-    .then(() => done())
-    .catch(done);
+    .then(dataSocket => {
+      expect(dataSocket.connected).to.equal(true);
+      expect(dataSocket instanceof net.Socket).to.equal(true);
+      expect(dataSocket instanceof tls.TLSSocket).to.equal(true);
+    });
   });
 });
diff --git a/test/connector/passive.spec.js b/test/connector/passive.spec.js
index 116f0976..783805bb 100644
--- a/test/connector/passive.spec.js
+++ b/test/connector/passive.spec.js
@@ -20,6 +20,10 @@ describe('Connector - Passive //', function () {
   };
   let sandbox;
 
+  function shouldNotResolve() {
+    throw new Error('Should not resolve');
+  }
+
   before(() => {
     passive = new PassiveConnector(mockConnection);
   });
@@ -36,45 +40,49 @@ describe('Connector - Passive //', function () {
     sandbox.restore();
   });
 
-  it('cannot wait for connection with no server', function (done) {
-    passive.waitForConnection()
-    .then(() => done('should not happen'))
+  it('cannot wait for connection with no server', function () {
+    return passive.waitForConnection()
+    .then(shouldNotResolve)
+    .catch(err => {
+      expect(err.name).to.equal('ConnectorError');
+    });
+  });
+
+  it('no pasv range provided', function () {
+    delete mockConnection.server.options.pasv_range;
+
+    return passive.setupServer()
+    .then(shouldNotResolve)
     .catch(err => {
       expect(err.name).to.equal('ConnectorError');
-      done();
     });
   });
 
-  it('has invalid pasv range', function (done) {
+  it('has invalid pasv range', function () {
     mockConnection.server.options.pasv_range = -1;
 
-    passive.setupServer()
-    .then(() => done('should not happen'))
+    return passive.setupServer()
+    .then(shouldNotResolve)
     .catch(err => {
       expect(err.name).to.equal('RangeError');
-      done();
     });
   });
 
-  it('sets up a server', function (done) {
-    passive.setupServer()
+  it('sets up a server', function () {
+    return passive.setupServer()
     .then(() => {
       expect(passive.dataServer).to.exist;
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('destroys existing server, then sets up a server', function (done) {
+  it('destroys existing server, then sets up a server', function () {
     const closeFnSpy = sandbox.spy(passive.dataServer, 'close');
 
-    passive.setupServer()
+    return passive.setupServer()
     .then(() => {
       expect(closeFnSpy.callCount).to.equal(1);
       expect(passive.dataServer).to.exist;
-      done();
-    })
-    .catch(done);
+    });
   });
 
   it('refuses connection with different remote address', function (done) {
@@ -97,8 +105,8 @@ describe('Connector - Passive //', function () {
     .catch(done);
   });
 
-  it('accepts connection', function (done) {
-    passive.setupServer()
+  it('accepts connection', function () {
+    return passive.setupServer()
     .then(() => {
       expect(passive.dataServer).to.exist;
 
@@ -109,8 +117,6 @@ describe('Connector - Passive //', function () {
     .then(() => {
       expect(passive.dataSocket).to.exist;
       passive.end();
-      done();
-    })
-    .catch(done);
+    });
   });
 });
diff --git a/test/helpers/escape-path.spec.js b/test/helpers/escape-path.spec.js
index d91cf40a..802d99d2 100644
--- a/test/helpers/escape-path.spec.js
+++ b/test/helpers/escape-path.spec.js
@@ -2,10 +2,9 @@ const {expect} = require('chai');
 const escapePath = require('../../src/helpers/escape-path');
 
 describe('helpers // escape-path', function () {
-  it('escapes quotes', done => {
+  it('escapes quotes', () => {
     const string = '"test"';
     const escapedString = escapePath(string);
     expect(escapedString).to.equal('""test""');
-    done();
   });
 });
diff --git a/test/helpers/find-port.spec.js b/test/helpers/find-port.spec.js
index cc894db6..567b5b88 100644
--- a/test/helpers/find-port.spec.js
+++ b/test/helpers/find-port.spec.js
@@ -17,22 +17,19 @@ describe('helpers // find-port', function () {
     sandbox.restore();
   });
 
-  it('finds a port', done => {
-    findPort(1)
+  it('finds a port', () => {
+    return findPort(1)
     .then(port => {
       expect(Server.prototype.listen.callCount).to.be.above(1);
       expect(port).to.be.above(1);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('does not find a port', done => {
-    findPort(1, 2)
-    .then(() => done('no'))
+  it('does not find a port', () => {
+    return findPort(1, 2)
+    .then(() => expect(1).to.equal(2)) // should not happen
     .catch(err => {
       expect(err).to.exist;
-      done();
     });
   });
 });
diff --git a/test/helpers/resolve-host.spec.js b/test/helpers/resolve-host.spec.js
index 26c2be04..8762eaca 100644
--- a/test/helpers/resolve-host.spec.js
+++ b/test/helpers/resolve-host.spec.js
@@ -1,36 +1,51 @@
 const {expect} = require('chai');
+const sinon = require('sinon');
 const resolveHost = require('../../src/helpers/resolve-host');
 
 describe('helpers //resolve-host', function () {
   this.timeout(4000);
 
-  it('fetches ip address', done => {
+  let sandbox;
+  beforeEach(() => {
+    sandbox = sinon.sandbox.create();
+  });
+  afterEach(() => sandbox.restore());
+
+  it('fetches ip address', () => {
     const hostname = '0.0.0.0';
-    resolveHost(hostname)
+    return resolveHost(hostname)
     .then(resolvedHostname => {
       expect(resolvedHostname).to.match(/^\d+\.\d+\.\d+\.\d+$/);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('fetches ip address', done => {
+  it('fetches ip address', () => {
     const hostname = null;
-    resolveHost(hostname)
+    return resolveHost(hostname)
     .then(resolvedHostname => {
       expect(resolvedHostname).to.match(/^\d+\.\d+\.\d+\.\d+$/);
-      done();
-    })
-    .catch(done);
+    });
   });
 
-  it('does nothing', done => {
+  it('does nothing', () => {
     const hostname = '127.0.0.1';
-    resolveHost(hostname)
+    return resolveHost(hostname)
     .then(resolvedHostname => {
       expect(resolvedHostname).to.equal(hostname);
-      done();
-    })
-    .catch(done);
+    });
+  });
+
+  it('fails on getting hostname', () => {
+    sandbox.stub(require('http'), 'get').callsFake(function (url, cb) {
+      cb({
+        statusCode: 420
+      });
+    });
+
+    return resolveHost(null)
+    .then(() => expect(1).to.equal(2))
+    .catch(err => {
+      expect(err.code).to.equal(420);
+    });
   });
 });
diff --git a/test/index.spec.js b/test/index.spec.js
index f21c5ea9..53c5320f 100644
--- a/test/index.spec.js
+++ b/test/index.spec.js
@@ -14,7 +14,7 @@ describe('FtpServer', function () {
   let server;
   let client;
 
-  before(done => {
+  before(() => {
     server = new FtpServer(process.env.FTP_URL, {
       log,
       pasv_range: process.env.PASV_RANGE,
@@ -22,14 +22,14 @@ describe('FtpServer', function () {
         key: `${process.cwd()}/test/cert/server.key`,
         cert: `${process.cwd()}/test/cert/server.crt`,
         ca: `${process.cwd()}/test/cert/server.csr`
-      }
+      },
+      greeting: ['hello', 'world']
     });
     server.on('login', (data, resolve) => {
       resolve({root: process.cwd()});
     });
 
-    server.listen()
-    .then(() => done());
+    return server.listen();
   });
   after(() => {
     server.close();