diff --git a/tests/problems/space/test_alignment_problem.py b/tests/problems/space/test_alignment_problem.py
index 31e3de91..166cafad 100644
--- a/tests/problems/space/test_alignment_problem.py
+++ b/tests/problems/space/test_alignment_problem.py
@@ -1,5 +1,5 @@
 from pathlib import Path
-from typing import Any, Literal, Mapping, Optional
+from typing import Any, Callable, Literal, Mapping, Optional
 
 import pytest
 
@@ -197,7 +197,10 @@ def test_pass_arguments(self, adata_space_rotate: AnnData, args_to_check: Mappin
         args = gw_solver_args if args_to_check["rank"] == -1 else gw_lr_solver_args
         for arg, val in args.items():
             assert hasattr(solver, val)
-            assert getattr(solver, val) == args_to_check[arg]
+            if arg == "initializer":
+                assert isinstance(getattr(solver, val), Callable)
+            else:
+                assert getattr(solver, val) == args_to_check[arg]
 
         sinkhorn_solver = solver.linear_solver if args_to_check["rank"] == -1 else solver
         lin_solver_args = gw_linear_solver_args if args_to_check["rank"] == -1 else gw_lr_linear_solver_args
diff --git a/tests/problems/time/test_temporal_problem.py b/tests/problems/time/test_temporal_problem.py
index c5ec8e08..5a81ae57 100644
--- a/tests/problems/time/test_temporal_problem.py
+++ b/tests/problems/time/test_temporal_problem.py
@@ -1,4 +1,4 @@
-from typing import Any, List, Mapping, Optional
+from typing import Any, Callable, List, Mapping, Optional
 
 import pytest
 
@@ -442,7 +442,10 @@ def test_pass_arguments(self, adata_time: AnnData, args_to_check: Mapping[str, A
         for arg, val in args.items():
             assert hasattr(solver, val)
             el = getattr(solver, val)[0] if isinstance(getattr(solver, val), tuple) else getattr(solver, val)
-            assert el == args_to_check[arg]
+            if arg == "initializer":
+                assert isinstance(el, Callable)
+            else:
+                assert el == args_to_check[arg]
 
         lin_prob = problem[key]._solver._problem
         for arg, val in lin_prob_args.items():