diff --git a/swh/objstorage/tests/test_objstorage_seaweedfs.py b/swh/objstorage/tests/test_objstorage_seaweedfs.py
--- a/swh/objstorage/tests/test_objstorage_seaweedfs.py
+++ b/swh/objstorage/tests/test_objstorage_seaweedfs.py
@@ -7,6 +7,8 @@
 
 from typing import Optional
 
+from swh.objstorage.objstorage import decompressors
+
 from swh.objstorage.backends.seaweed import WeedObjStorage, DEFAULT_LIMIT
 from swh.objstorage.tests.objstorage_testing import ObjStorageTestFixture
 
@@ -48,6 +50,16 @@
                                       compression=self.compression)
         self.storage.wf = MockWeedFiler(self.url)
 
+    def test_compression(self):
+        content, obj_id = self.hash_content(b'test compression')
+        self.storage.add(content, obj_id=obj_id)
+
+        raw_content = self.storage.wf.get(self.storage._path(obj_id))
+
+        d = decompressors[self.compression]()
+        assert d.decompress(raw_content) == content
+        assert d.unused_data == b''
+
 
 class TestWeedObjStorageBz2(TestWeedObjStorage):
     compression = 'bz2'