@@ -75,19 +75,18 @@ def test_hamiltonian_submatrix(vectorize):

     raises(ValueError, kwant.solvers.default.greens_function, syst3, 0.2)

     # Test for shape errors.

-    syst[chain2(0), chain(2)] = np.array([[1, 2]])

-    syst2 = syst.finalized()

-    raises(ValueError, syst2.hamiltonian_submatrix)

-    raises(ValueError, syst2.hamiltonian_submatrix, sparse=True)

-    syst[chain2(0), chain(2)] = 1

-    syst2 = syst.finalized()

-    raises(ValueError, syst2.hamiltonian_submatrix)

-    raises(ValueError, syst2.hamiltonian_submatrix, sparse=True)

-    if vectorize:  # non-vectorized systems don't check this at finalization

-        # Add another hopping of the same type but with a different

-        # (and still incompatible) shape.

-        syst[chain2(0), chain(1)] = np.array([[1, 2]])

-        raises(ValueError, syst.finalized)

+    badly_shaped_hoppings = [

+        1,

+        [[1, 2]],  # shape (1, 2) instead of (2, 1)

+        lambda a, b: 1,

+        lambda a, b: [[1, 2]],

+    ]

+    for hopping in badly_shaped_hoppings:

+        syst[chain2(0), chain(2)] = hopping

+        with raises(ValueError):

+            syst.finalized().hamiltonian_submatrix(sparse=False)

+        with raises(ValueError):

+            syst.finalized().hamiltonian_submatrix(sparse=True)

 @pytest.mark.parametrize("vectorize", [False, True])