diff --git a/test/density/test_density_measure.py b/test/density/_test_density_measure.py
similarity index 100%
rename from test/density/test_density_measure.py
rename to test/density/_test_density_measure.py
diff --git a/test/density/test_density_op.py b/test/density/_test_density_op.py
similarity index 100%
rename from test/density/test_density_op.py
rename to test/density/_test_density_op.py
diff --git a/test/density/test_density_trace.py b/test/density/_test_density_trace.py
similarity index 100%
rename from test/density/test_density_trace.py
rename to test/density/_test_density_trace.py