diff --git a/pybamm/solvers/casadi_solver.py b/pybamm/solvers/casadi_solver.py
index 2d657c0cc0..d05e6283f9 100644
--- a/pybamm/solvers/casadi_solver.py
+++ b/pybamm/solvers/casadi_solver.py
@@ -153,6 +153,7 @@ def _integrate(self, model, t_eval, inputs=None):
                 # Initialize solution
                 solution = pybamm.Solution(np.array([t]), y0[:, np.newaxis])
                 solution.solve_time = 0
+                solution.integration_time = 0
             else:
                 solution = None
 
diff --git a/tests/unit/test_expression_tree/test_unary_operators.py b/tests/unit/test_expression_tree/test_unary_operators.py
index e952ac9273..165f8fd88c 100644
--- a/tests/unit/test_expression_tree/test_unary_operators.py
+++ b/tests/unit/test_expression_tree/test_unary_operators.py
@@ -47,8 +47,8 @@ def test_smooth_absolute_value(self):
         self.assertAlmostEqual(expr.evaluate(y=np.array([-1]))[0, 0], 1)
         self.assertEqual(
             str(expr),
-            "y[0:1] * exp(10.0 * y[0:1]) - exp(-10.0 * y[0:1]) "
-            "/ exp(10.0 * y[0:1]) + exp(-10.0 * y[0:1])",
+            "y[0:1] * (exp(10.0 * y[0:1]) - exp(-10.0 * y[0:1])) "
+            "/ (exp(10.0 * y[0:1]) + exp(-10.0 * y[0:1]))",
         )
 
     def test_sign(self):
diff --git a/tests/unit/test_solvers/test_solution.py b/tests/unit/test_solvers/test_solution.py
index 99c5a67a7a..d2cc7fb967 100644
--- a/tests/unit/test_solvers/test_solution.py
+++ b/tests/unit/test_solvers/test_solution.py
@@ -31,6 +31,7 @@ def test_append(self):
         y1 = np.tile(t1, (20, 1))
         sol1 = pybamm.Solution(t1, y1)
         sol1.solve_time = 1.5
+        sol1.integration_time = 0.3
         sol1.model = pybamm.BaseModel()
         sol1.inputs = {"a": 1}
 
@@ -39,11 +40,13 @@ def test_append(self):
         y2 = np.tile(t2, (20, 1))
         sol2 = pybamm.Solution(t2, y2)
         sol2.solve_time = 1
+        sol2.integration_time = 0.5
         sol2.inputs = {"a": 2}
         sol1.append(sol2, create_sub_solutions=True)
 
         # Test
         self.assertEqual(sol1.solve_time, 2.5)
+        self.assertEqual(sol1.integration_time, 0.8)
         np.testing.assert_array_equal(sol1.t, np.concatenate([t1, t2[1:]]))
         np.testing.assert_array_equal(sol1.y, np.concatenate([y1, y2[:, 1:]], axis=1))
         np.testing.assert_array_equal(