diff --git a/requirements-test.txt b/requirements-test.txt
--- a/requirements-test.txt
+++ b/requirements-test.txt
@@ -7,3 +7,8 @@
 
 types-click
 types-pyyaml
+
+# Flask: dependency of swh-core
+# version 2.2.0 is causing test failures
+# cf https://forge.softwareheritage.org/T4416
+Flask != 2.2.0