Fix accidental switch of previous and next

We were showing the previous page link when we meant to show the next
page link because the variables were swapped round in the code.

app/main/views/uploads.py

@@ -46,10 +46,10 @@ def uploads(service_id):
     uploads = current_service.get_page_of_uploads(page=request.args.get('page'))
 
     prev_page = None
-    if uploads.next_page:
+    if uploads.prev_page:
         prev_page = generate_previous_dict('main.uploads', service_id, uploads.current_page)
     next_page = None
-    if uploads.prev_page:
+    if uploads.next_page:
         next_page = generate_next_dict('main.uploads', service_id, uploads.current_page)
 
     if uploads.current_page == 1:

tests/app/main/views/test_uploads.py

@@ -660,3 +660,21 @@ def test_uploads_page_shows_scheduled_jobs(
         ),
     ]
     assert not page.select('.table-empty-message')
+
+
+def test_get_uploads_shows_pagination(
+    client_request,
+    active_user_with_permissions,
+    mock_get_jobs,
+    mock_get_uploads,
+):
+    page = client_request.get('main.uploads', service_id=SERVICE_ONE_ID)
+
+    assert normalize_spaces(page.select_one('.next-page').text) == (
+        'Next page '
+        'page 2'
+    )
+    assert normalize_spaces(page.select_one('.previous-page').text) == (
+        'Previous page '
+        'page 0'
+    )