diff --git a/tests/regression_tests/lattice_multiple/test.py b/tests/regression_tests/lattice_multiple/test.py
index a9b15c9c85..c287c01027 100644
--- a/tests/regression_tests/lattice_multiple/test.py
+++ b/tests/regression_tests/lattice_multiple/test.py
@@ -22,12 +22,8 @@ def model():
 
     cyl = openmc.ZCylinder(r=0.4)
     big_cyl = openmc.ZCylinder(r=0.5)
-    c1 = openmc.Cell(fill=uo2, region=-cyl)
-    c2 = openmc.Cell(fill=water, region=+cyl)
-    pin = openmc.Universe(cells=[c1, c2])
-    c3 = openmc.Cell(fill=uo2, region=-big_cyl)
-    c4 = openmc.Cell(fill=water, region=+big_cyl)
-    big_pin = openmc.Universe(cells=[c3, c4])
+    pin = openmc.model.pin([cyl], [uo2, water])
+    big_pin = openmc.model.pin([big_cyl], [uo2, water])
 
     d = 1.2
     inner_lattice = openmc.RectLattice()
diff --git a/tests/regression_tests/tally_aggregation/test.py b/tests/regression_tests/tally_aggregation/test.py
index 8914ac2a8e..70a948be67 100644
--- a/tests/regression_tests/tally_aggregation/test.py
+++ b/tests/regression_tests/tally_aggregation/test.py
@@ -24,9 +24,7 @@ def model():
     model.materials.extend([fuel, water])
 
     cyl = openmc.ZCylinder(r=0.4)
-    c1 = openmc.Cell(fill=fuel, region=-cyl)
-    c2 = openmc.Cell(fill=water, region=+cyl)
-    pin = openmc.Universe(cells=[c1, c2])
+    pin = openmc.model.pin([cyl], [fuel, water])
     d = 1.2
     lattice = openmc.RectLattice()
     lattice.lower_left = (-d, -d)
@@ -45,7 +43,7 @@ def model():
     model.settings.particles = 1000
 
     energy_filter = openmc.EnergyFilter([0.0, 0.253, 1.0e3, 1.0e6, 20.0e6])
-    distrib_filter = openmc.DistribcellFilter(c1)
+    distrib_filter = openmc.DistribcellFilter(pin.cells[1])
     tally = openmc.Tally(name='distribcell tally')
     tally.filters = [energy_filter, distrib_filter]
     tally.scores = ['nu-fission', 'total']
diff --git a/tests/regression_tests/tally_assumesep/tallies.xml b/tests/regression_tests/tally_assumesep/tallies.xml
index 1e1c5492af..f65e5dfec6 100644
--- a/tests/regression_tests/tally_assumesep/tallies.xml
+++ b/tests/regression_tests/tally_assumesep/tallies.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 <tallies>
 
-  <assume_separate>false</assume_separate>
+  <assume_separate>true</assume_separate>
 
   <filter id="1">
     <type>cell</type>