diff --git a/tox.ini b/tox.ini
index 3ee544538a09..0e0041edd834 100644
--- a/tox.ini
+++ b/tox.ini
@@ -4,6 +4,7 @@ envlist = py38, py39, py310, py311, py312, lint-incr
 isolated_build = true
 
 [testenv]
+usedevelop = True
 # The colons in the substitutions below let us re-use the `install_command` in
 # places where `tox` doesn't automatically fill in those values.
 install_command = pip install -c{toxinidir}/constraints.txt -U {opts:} {packages:}