diff --git a/swh/deposit/tests/api/test_deposit_atom.py b/swh/deposit/tests/api/test_deposit_atom.py
--- a/swh/deposit/tests/api/test_deposit_atom.py
+++ b/swh/deposit/tests/api/test_deposit_atom.py
@@ -54,8 +54,10 @@
         reverse(COL_IRI, args=[deposit_collection.name]),
         content_type="application/atom+xml;type=entry",
         data=atom_dataset["entry-data-empty-body"],
+        HTTP_SLUG="something",
     )
     assert response.status_code == status.HTTP_400_BAD_REQUEST
+    assert b"Empty body request is not supported" in response.content
 
 
 def test_post_deposit_atom_400_badly_formatted_atom(
diff --git a/swh/deposit/tests/data/atom/entry-data-empty-body.xml b/swh/deposit/tests/data/atom/entry-data-empty-body.xml
--- a/swh/deposit/tests/data/atom/entry-data-empty-body.xml
+++ b/swh/deposit/tests/data/atom/entry-data-empty-body.xml
@@ -1,2 +1,2 @@
 <?xml version="1.0"?>
-<entry xmlns="http://www.w3.org/2005/Atom"></entry>
+<entry></entry>