Only check on csv is the file extension.

Update validator logic

Update message for the validator.

app/main/validators.py

@@ -20,8 +20,8 @@ class CsvFileValidator(object):
         self.message = message
 
     def __call__(self, form, field):
-        if not form.file.data.mimetype == 'text/csv':
-            raise ValidationError(self.message)
+        if not field.data.filename.lower().endswith('.csv'):
+            raise ValidationError("{} is not a CSV file".format(field.data.filename))
 
 
 class ValidEmailDomainRegex(object):

tests/app/main/views/test_send.py

@@ -51,6 +51,32 @@ def test_upload_csvfile_with_errors_shows_check_page_with_errors(
             assert 'Re-upload your file' in content
 
 
+def test_upload_csv_invalid_extension(app_,
+                                      api_user_active,
+                                      mock_login,
+                                      mock_get_service,
+                                      mock_get_service_template,
+                                      mock_s3_upload,
+                                      mock_has_permissions,
+                                      mock_get_users_by_service,
+                                      mock_get_service_statistics,
+                                      fake_uuid):
+    contents = u'phone number,name\n+44 123,test1\n+44 456,test2'
+    with app_.test_request_context():
+        filename = 'invalid.txt'
+        with app_.test_client() as client:
+            client.login(api_user_active)
+            resp = client.post(
+                url_for('main.send_messages', service_id=fake_uuid, template_id=fake_uuid),
+                data={'file': (BytesIO(contents.encode('utf-8')), filename)},
+                content_type='multipart/form-data',
+                follow_redirects=True
+            )
+
+        assert resp.status_code == 200
+        assert "{} is not a CSV file".format(filename) in resp.get_data(as_text=True)
+
+
 def test_send_test_sms_message_to_self(
     app_,
     mocker,

tests/conftest.py

@@ -635,7 +635,7 @@ def mock_get_no_api_keys(mocker):
 
 
 @pytest.fixture(scope='function')
-def mock_login(mocker, mock_get_user, mock_update_user):
+def mock_login(mocker, mock_get_user, mock_update_user, mock_events):
     def _verify_code(user_id, code, code_type):
         return True, ''