diff --git a/haiku/_src/base_test.py b/haiku/_src/base_test.py
index f23336ff1..56fa32774 100644
--- a/haiku/_src/base_test.py
+++ b/haiku/_src/base_test.py
@@ -106,6 +106,12 @@ def replace_rng_sequence_state_example():
 
 class BaseTest(parameterized.TestCase):
 
+  def assert_keys_equal(self, a, b):
+    self.assertEqual(jax.random.key_impl(a), jax.random.key_impl(b))
+    np.testing.assert_array_equal(
+        jax.random.key_data(a), jax.random.key_data(b)
+    )
+
   @test_utils.transform_and_run
   def test_parameter_reuse(self):
     w1 = base.get_parameter("w", [], init=jnp.zeros)
@@ -646,7 +652,7 @@ def test_prng_reserve(self):
     s.reserve(10)
     hk_keys = tuple(next(s) for _ in range(10))
     jax_keys = tuple(jax.random.split(test_utils.clone(k), num=11)[1:])
-    jax.tree.map(np.testing.assert_array_equal, hk_keys, jax_keys)
+    jax.tree.map(self.assert_keys_equal, hk_keys, jax_keys)
 
   def test_prng_reserve_twice(self):
     k = jax.random.PRNGKey(42)
@@ -657,14 +663,14 @@ def test_prng_reserve_twice(self):
     k, subkey1, subkey2 = tuple(jax.random.split(test_utils.clone(k), num=3))
     _, subkey3, subkey4 = tuple(jax.random.split(k, num=3))
     jax_keys = (subkey1, subkey2, subkey3, subkey4)
-    jax.tree.map(np.testing.assert_array_equal, hk_keys, jax_keys)
+    jax.tree.map(self.assert_keys_equal, hk_keys, jax_keys)
 
   def test_prng_sequence_split(self):
     k = jax.random.PRNGKey(42)
     s = base.PRNGSequence(k)
     hk_keys = s.take(10)
     jax_keys = tuple(jax.random.split(test_utils.clone(k), num=11)[1:])
-    jax.tree.map(np.testing.assert_array_equal, hk_keys, jax_keys)
+    jax.tree.map(self.assert_keys_equal, hk_keys, jax_keys)
 
   @parameterized.parameters(42, 28)
   def test_with_rng(self, seed):
@@ -782,7 +788,7 @@ def test_rng_reserve_size(self):
       for _ in range(2):
         split_key, *expected_keys = jax.random.split(split_key, size+1)
         hk_keys = hk.next_rng_keys(size)
-        np.testing.assert_array_equal(hk_keys, expected_keys)
+        jax.tree.map(self.assert_keys_equal, list(hk_keys), expected_keys)
 
   @parameterized.parameters(
       base.get_params, base.get_current_state, base.get_initial_state
diff --git a/haiku/_src/stateful_test.py b/haiku/_src/stateful_test.py
index c4e3f03c2..e3be583cf 100644
--- a/haiku/_src/stateful_test.py
+++ b/haiku/_src/stateful_test.py
@@ -87,26 +87,37 @@ def wrapper(*a, **kw):
 
 class StatefulTest(parameterized.TestCase):
 
+  def assert_keys_equal(self, a, b):
+    self.assertEqual(jax.random.key_impl(a), jax.random.key_impl(b))
+    np.testing.assert_array_equal(
+        jax.random.key_data(a), jax.random.key_data(b)
+    )
+
+  def assert_keys_not_equal(self, a, b):
+    self.assertFalse(
+        (jax.random.key_impl(a) == jax.random.key_impl(b)) and
+        (jnp.all(jax.random.key_data(a) == jax.random.key_data(b))))
+
   @test_utils.transform_and_run
   def test_grad(self):
-    x = jnp.array(3.)
+    x = jnp.array(3.0)
     g = stateful.grad(SquareModule())(x)
     np.testing.assert_allclose(g, 2 * x, rtol=1e-4)
 
   def test_grad_no_transform(self):
-    x = jnp.array(3.)
+    x = jnp.array(3.0)
     with self.assertRaises(ValueError, msg="Use jax.grad() instead"):
       stateful.grad(jnp.square)(x)
 
   @test_utils.transform_and_run
   def test_value_and_grad(self):
-    x = jnp.array(2.)
+    x = jnp.array(2.0)
     y, g = stateful.value_and_grad(SquareModule())(x)
-    self.assertEqual(y, x ** 2)
+    self.assertEqual(y, x**2)
     np.testing.assert_allclose(g, 2 * x, rtol=1e-4)
 
   def test_value_and_grad_no_transform(self):
-    x = jnp.array(3.)
+    x = jnp.array(3.0)
     with self.assertRaises(ValueError, msg="Use jax.grad() instead"):
       stateful.value_and_grad(jnp.square)(x)
 
@@ -645,12 +656,12 @@ def test_vmap_no_split_rng(self):
     x = jnp.arange(4)
     k1, k2, k3, k4 = f(x)
     key_after = base.next_rng_key()
-    np.testing.assert_array_equal(k1, k2)
-    np.testing.assert_array_equal(k2, k3)
-    np.testing.assert_array_equal(k3, k4)
-    self.assertFalse(np.array_equal(key_before, k1))
-    self.assertFalse(np.array_equal(key_after, k1))
-    self.assertFalse(np.array_equal(key_before, key_after))
+    self.assert_keys_equal(k1, k2)
+    self.assert_keys_equal(k2, k3)
+    self.assert_keys_equal(k3, k4)
+    self.assert_keys_not_equal(key_before, k1)
+    self.assert_keys_not_equal(key_after, k1)
+    self.assert_keys_not_equal(key_before, key_after)
 
   @test_utils.transform_and_run
   def test_vmap_split_rng(self):