diff --git a/pytest.ini b/pytest.ini
--- a/pytest.ini
+++ b/pytest.ini
@@ -4,4 +4,5 @@
 filterwarnings =
     ignore:.*Plural value must be an integer, got float
     ignore:.*Using or importing the ABCs from 'collections'
-
+    ignore:.*uses the 'client' fixture, but function-scoped
+    ignore:.*uses the 'mocker' fixture, but function-scoped
diff --git a/swh/web/tests/conftest.py b/swh/web/tests/conftest.py
--- a/swh/web/tests/conftest.py
+++ b/swh/web/tests/conftest.py
@@ -110,7 +110,7 @@
 
 
 # Initialize tests data
-@pytest.fixture(autouse=True)
+@pytest.fixture(scope='session', autouse=True)
 def tests_data():
     data = get_tests_data(reset=True)
     # Update swh-web configuration to use the in-memory storages
@@ -120,13 +120,13 @@
 
 
 # Fixture to manipulate data from a sample archive used in the tests
-@pytest.fixture
+@pytest.fixture(scope='session')
 def archive_data(tests_data):
     return _ArchiveData(tests_data)
 
 
 # Fixture to manipulate indexer data from a sample archive used in the tests
-@pytest.fixture
+@pytest.fixture(scope='session')
 def indexer_data(tests_data):
     return _IndexerData(tests_data)