diff --git a/cirq-core/cirq/contrib/acquaintance/topological_sort_test.py b/cirq-core/cirq/contrib/acquaintance/topological_sort_test.py
index c13a9e430c8..c813b7f913f 100644
--- a/cirq-core/cirq/contrib/acquaintance/topological_sort_test.py
+++ b/cirq-core/cirq/contrib/acquaintance/topological_sort_test.py
@@ -21,7 +21,7 @@
 @pytest.mark.parametrize(
     'circuit_dag,sorted_nodes',
     [
-        (dag, cca.random_topological_sort(dag))
+        (dag, tuple(cca.random_topological_sort(dag)))
         for dag in [
             cirq.CircuitDag.from_circuit(cirq.testing.random_circuit(10, 10, 0.5)) for _ in range(5)
         ]
diff --git a/cirq-core/cirq/study/sweeps_test.py b/cirq-core/cirq/study/sweeps_test.py
index a9fec7229ef..4da1008a9df 100644
--- a/cirq-core/cirq/study/sweeps_test.py
+++ b/cirq-core/cirq/study/sweeps_test.py
@@ -134,16 +134,18 @@ def test_access_sweep():
     assert sixth_elem == cirq.ParamResolver({'a': 2, 'b': 5})
 
 
+# We use factories since some of these produce generators and we want to
+# test for passing in a generator to initializer.
 @pytest.mark.parametrize(
-    'r_list',
+    'r_list_factory',
     [
-        [{'a': a, 'b': a + 1} for a in (0, 0.5, 1, -10)],
-        ({'a': a, 'b': a + 1} for a in (0, 0.5, 1, -10)),
-        ({sympy.Symbol('a'): a, 'b': a + 1} for a in (0, 0.5, 1, -10)),
+        lambda: [{'a': a, 'b': a + 1} for a in (0, 0.5, 1, -10)],
+        lambda: ({'a': a, 'b': a + 1} for a in (0, 0.5, 1, -10)),
+        lambda: ({sympy.Symbol('a'): a, 'b': a + 1} for a in (0, 0.5, 1, -10)),
     ],
 )
-def test_list_sweep(r_list):
-    sweep = cirq.ListSweep(r_list)
+def test_list_sweep(r_list_factory):
+    sweep = cirq.ListSweep(r_list_factory())
     assert sweep.keys == ['a', 'b']
     assert len(sweep) == 4
     assert len(list(sweep)) == 4
diff --git a/cirq-core/cirq/testing/circuit_compare_test.py b/cirq-core/cirq/testing/circuit_compare_test.py
index c3391d71e44..75e453f7f63 100644
--- a/cirq-core/cirq/testing/circuit_compare_test.py
+++ b/cirq-core/cirq/testing/circuit_compare_test.py
@@ -133,9 +133,10 @@ def test_random_same_matrix(circuit):
 
     cirq.testing.assert_circuits_with_terminal_measurements_are_equivalent(circuit, same)
 
-    circuit.append(cirq.measure(a))
+    mutable_circuit = circuit.copy()
+    mutable_circuit.append(cirq.measure(a))
     same.append(cirq.measure(a))
-    cirq.testing.assert_circuits_with_terminal_measurements_are_equivalent(circuit, same)
+    cirq.testing.assert_circuits_with_terminal_measurements_are_equivalent(mutable_circuit, same)
 
 
 def test_correct_qubit_ordering():