diff --git a/jwst/associations/tests/test_level3_product_names.py b/jwst/associations/tests/test_level3_product_names.py
index 1da85ce9a6b..74213b024b4 100644
--- a/jwst/associations/tests/test_level3_product_names.py
+++ b/jwst/associations/tests/test_level3_product_names.py
@@ -96,7 +96,7 @@ def test_level3_names(pool_file, global_constraints):
     rules = registry_level3_only(
         global_constraints=global_constraints
     )
-    pool = AssociationPool.read(pool_file)
+    pool = combine_pools(pool_file)
     asns = generate(pool, rules)
     for asn in asns:
         product_name = asn['products'][0]['name']
@@ -110,8 +110,8 @@ def test_level3_names(pool_file, global_constraints):
 
 def test_multiple_optelems(pool_file):
     rules = registry_level3_only()
-    pool = AssociationPool.read(pool_file)
-    asns = generate(pool, rules)
+    pool = combine_pools(pool_file)
+    asns = generate(pool, rules, finalize=False)
     for asn in asns:
         product_name = asn['products'][0]['name']
         if asn['asn_rule'] != 'Asn_Lv3MIRMRS':
@@ -137,7 +137,37 @@ def test_multiple_optelems(pool_file):
                     value = '-'.join(asn.constraints[extra].found_values)
                 except KeyError:
                     value = None
-                if value not in EMPTY:
+
+                # empty values and subarray = full are not recorded
+                if value not in EMPTY and value != 'full':
                     values.append(value)
 
             assert m.groupdict()['opt_elem'] == '-'.join(values)
+
+
+def test_tso3_names():
+    rules = registry_level3_only()
+    tso_pool = t_path('data/pool_021_tso.csv')
+    pool = combine_pools(tso_pool)
+    asns = generate(pool, rules, finalize=False)
+    for asn in asns:
+        product_name = asn['products'][0]['name']
+
+        m = re.match(LEVEL3_PRODUCT_NAME_REGEX, product_name)
+        assert m is not None
+
+        # there should always be an opt_elem
+        values = ['-'.join(asn.constraints['opt_elem'].found_values)]
+
+        # there may also be an opt_elem2, fixed slit or 2, or a subarray
+        for extra in ['opt_elem2', 'fxd_slit', 'fxd_slit2', 'subarray']:
+            try:
+                value = '-'.join(asn.constraints[extra].found_values)
+            except KeyError:
+                value = None
+
+            # empty values and subarray = full are not recorded
+            if value not in EMPTY and value != 'full':
+                values.append(value)
+
+        assert m.groupdict()['opt_elem'] == '-'.join(values)