diff --git a/.travis.yml b/.travis.yml
index 9e286448..99ad7ade 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -21,6 +21,9 @@ before_install:
     - sudo mysql -e "use mysql; update user set authentication_string=PASSWORD('password') where User='root'; update user set plugin='mysql_native_password';FLUSH PRIVILEGES;"
     - sudo mysql_upgrade -u root -ppassword
     - sudo service mysql restart
+    - sudo rm -f /etc/boto.cfg
+    - export AWS_SECRET_ACCESS_KEY=AKIAIOSFODNN7EXAMPLE
+    - export AWS_ACCESS_KEY_ID=wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
 install:
     - pip install -r development.txt
 before_script:
diff --git a/CTFd/utils/uploads/uploaders.py b/CTFd/utils/uploads/uploaders.py
index 31eca7fe..e080ce02 100644
--- a/CTFd/utils/uploads/uploaders.py
+++ b/CTFd/utils/uploads/uploaders.py
@@ -97,6 +97,7 @@ class S3Uploader(BaseUploader):
 
     def upload(self, file_obj, filename):
         filename = filter(self._clean_filename, secure_filename(filename).replace(' ', '_'))
+        filename = ''.join(filename)
         if len(filename) <= 0:
             return False
 
@@ -122,7 +123,8 @@ class S3Uploader(BaseUploader):
 
     def sync(self):
         local_folder = current_app.config.get('UPLOAD_FOLDER')
-        bucket_list = self.s3.list_objects(Bucket=self.bucket)['Contents']
+        # If the bucket is empty then Contents will not be in the response
+        bucket_list = self.s3.list_objects(Bucket=self.bucket).get('Contents', [])
 
         for s3_key in bucket_list:
             s3_object = s3_key['Key']
diff --git a/development.txt b/development.txt
index 2d0ad2b0..bc4a521a 100644
--- a/development.txt
+++ b/development.txt
@@ -9,3 +9,4 @@ psycopg2==2.7.5
 psycopg2-binary==2.7.5
 codecov==2.0.15
 nose-randomly==1.2.5
+moto==1.3.7
diff --git a/tests/utils/test_uploaders.py b/tests/utils/test_uploaders.py
new file mode 100644
index 00000000..03bc5014
--- /dev/null
+++ b/tests/utils/test_uploaders.py
@@ -0,0 +1,59 @@
+import boto3
+from moto import mock_s3
+from tests.helpers import *
+from CTFd.utils.uploads import S3Uploader, FilesystemUploader, rmdir
+from CTFd.utils import binary_type
+from six import BytesIO
+import os
+
+
+@mock_s3
+def test_s3_uploader():
+    conn = boto3.resource('s3', region_name='us-east-1')
+    conn.create_bucket(Bucket='bucket')
+
+    app = create_ctfd()
+    with app.app_context():
+        app.config['UPLOAD_PROVIDER'] = 's3'
+        app.config['AWS_ACCESS_KEY_ID'] = 'AKIAIOSFODNN7EXAMPLE'
+        app.config['AWS_SECRET_ACCESS_KEY'] = 'wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY'
+        app.config['AWS_S3_BUCKET'] = 'bucket'
+
+        uploader = S3Uploader()
+
+        assert uploader.s3
+        assert uploader.bucket == 'bucket'
+
+        fake_file = BytesIO('fakedfile'.encode())
+        path = uploader.upload(fake_file, 'fake_file.txt')
+
+        assert 'fake_file.txt' in uploader.download(path).location
+    destroy_ctfd(app)
+
+
+@mock_s3
+def test_s3_sync():
+    conn = boto3.resource('s3', region_name='us-east-1')
+    conn.create_bucket(Bucket='bucket')
+
+    app = create_ctfd()
+    with app.app_context():
+        app.config['UPLOAD_PROVIDER'] = 's3'
+        app.config['AWS_ACCESS_KEY_ID'] = 'AKIAIOSFODNN7EXAMPLE'
+        app.config['AWS_SECRET_ACCESS_KEY'] = 'wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY'
+        app.config['AWS_S3_BUCKET'] = 'bucket'
+
+        uploader = S3Uploader()
+        uploader.sync()
+
+        fake_file = BytesIO('fakedfile'.encode())
+        path = uploader.upload(fake_file, 'fake_file.txt')
+        full_path = os.path.join(app.config['UPLOAD_FOLDER'], path)
+
+        try:
+            uploader.sync()
+            with open(full_path) as f:
+                assert f.read() == 'fakedfile'
+        finally:
+            rmdir(os.path.dirname(full_path))
+    destroy_ctfd(app)