diff --git a/app/main/uploader.py b/app/main/uploader.py
index a55eab1ea..cc1f708c3 100644
--- a/app/main/uploader.py
+++ b/app/main/uploader.py
@@ -1,3 +1,4 @@
+import uuid
 import botocore
 from boto3 import resource
 from flask import current_app
@@ -5,7 +6,7 @@ from flask import current_app
 FILE_LOCATION_STRUCTURE = 'service-{}-notify/{}.csv'
 
 
-def s3upload(upload_id, service_id, filedata, region):
+def s3upload(service_id, filedata, region):
     s3 = resource('s3')
     bucket_name = current_app.config['CSV_UPLOAD_BUCKET_NAME']
     contents = filedata['data']
@@ -27,10 +28,13 @@ def s3upload(upload_id, service_id, filedata, region):
         s3.create_bucket(Bucket=bucket_name,
                          CreateBucketConfiguration={'LocationConstraint': region})
 
+    upload_id = str(uuid.uuid4())
     upload_file_name = FILE_LOCATION_STRUCTURE.format(service_id, upload_id)
     key = s3.Object(bucket_name, upload_file_name)
     key.put(Body=contents, ServerSideEncryption='AES256')
 
+    return upload_id
+
 
 def s3download(service_id, upload_id):
     contents = ''
diff --git a/app/main/views/send.py b/app/main/views/send.py
index e015021a0..c48b4c61b 100644
--- a/app/main/views/send.py
+++ b/app/main/views/send.py
@@ -110,9 +110,7 @@ def send_messages(service_id, template_id):
     form = CsvUploadForm()
     if form.validate_on_submit():
         try:
-            upload_id = str(uuid.uuid4())
-            s3upload(
-                upload_id,
+            upload_id = s3upload(
                 service_id,
                 Spreadsheet.from_file(form.file.data.filename, form.file.data).as_dict,
                 current_app.config['AWS_REGION']
@@ -161,6 +159,8 @@ def get_example_csv(service_id, template_id):
 @user_has_permissions('send_texts', 'send_emails', 'send_letters')
 def send_test(service_id, template_id):
 
+    file_name = 'Test message'
+
     template = Template(
         service_api_client.get_service_template(service_id, template_id)['data'],
         prefix=current_service['name']
@@ -173,13 +173,18 @@ def send_test(service_id, template_id):
                 [first_column_heading[template.template_type]] + list(template.placeholders),
                 get_example_csv_rows(template, use_example_as_example=False, submitted_fields=request.form)
             ])
-            filedata = {
-                'file_name': 'Test message',
-                'data': output.getvalue()
+            upload_id = s3upload(
+                service_id,
+                {
+                    'file_name': file_name,
+                    'data': output.getvalue()
+                },
+                current_app.config['AWS_REGION']
+            )
+            session['upload_data'] = {
+                "template_id": template_id,
+                "original_file_name": file_name
             }
-            upload_id = str(uuid.uuid4())
-            s3upload(upload_id, service_id, filedata, current_app.config['AWS_REGION'])
-            session['upload_data'] = {"template_id": template_id, "original_file_name": filedata['file_name']}
             return redirect(url_for(
                 '.check_messages',
                 upload_id=upload_id,
diff --git a/tests/app/main/views/test_send.py b/tests/app/main/views/test_send.py
index 444e32247..61fad0881 100644
--- a/tests/app/main/views/test_send.py
+++ b/tests/app/main/views/test_send.py
@@ -53,7 +53,7 @@ def test_upload_files_in_different_formats(
         )
 
     if acceptable_file:
-        assert mock_s3_upload.call_args[0][2]['data'].strip() == (
+        assert mock_s3_upload.call_args[0][1]['data'].strip() == (
             "phone number,name,favourite colour,fruit\r\n"
             "07739 468 050,Pete,Coral,tomato\r\n"
             "07527 125 974,Not Pete,Magenta,Avacado\r\n"
@@ -157,7 +157,7 @@ def test_send_test_sms_message(
                 follow_redirects=True
             )
         assert response.status_code == 200
-        mock_s3_upload.assert_called_with(ANY, fake_uuid, expected_data, 'eu-west-1')
+        mock_s3_upload.assert_called_with(fake_uuid, expected_data, 'eu-west-1')
 
 
 def test_send_test_email_message(
@@ -185,7 +185,7 @@ def test_send_test_email_message(
                 follow_redirects=True
             )
         assert response.status_code == 200
-        mock_s3_upload.assert_called_with(ANY, fake_uuid, expected_data, 'eu-west-1')
+        mock_s3_upload.assert_called_with(fake_uuid, expected_data, 'eu-west-1')
 
 
 def test_send_test_sms_message_with_placeholders(
@@ -221,7 +221,7 @@ def test_send_test_sms_message_with_placeholders(
                 follow_redirects=True
             )
         assert response.status_code == 200
-        mock_s3_upload.assert_called_with(ANY, fake_uuid, expected_data, 'eu-west-1')
+        mock_s3_upload.assert_called_with(fake_uuid, expected_data, 'eu-west-1')
 
 
 def test_api_info_page(
diff --git a/tests/conftest.py b/tests/conftest.py
index 2a573f754..8cf48cf2b 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -816,8 +816,8 @@ def mock_get_users_by_service(mocker):
 
 @pytest.fixture(scope='function')
 def mock_s3_upload(mocker):
-    def _upload(upload_id, service_id, filedata, region):
-        pass
+    def _upload(service_id, filedata, region):
+        return fake_uuid()
     return mocker.patch('app.main.views.send.s3upload', side_effect=_upload)