diff --git a/trax/tf_numpy/jax_tests/lax_numpy_test.py b/trax/tf_numpy/jax_tests/lax_numpy_test.py
index 7600a1448..cf014f6f4 100644
--- a/trax/tf_numpy/jax_tests/lax_numpy_test.py
+++ b/trax/tf_numpy/jax_tests/lax_numpy_test.py
@@ -927,7 +927,7 @@ def onp_fun(a, b):
     check_xla = not set((lhs_dtype, rhs_dtype)).intersection(
         (onp.int32, onp.int64))
 
-    tol = {onp.float64: 1e-14}
+    tol = {onp.float64: 1e-14, onp.float16: 0.04}
     tol = max(jtu.tolerance(lhs_dtype, tol), jtu.tolerance(rhs_dtype, tol))
     self._CompileAndCheck(lnp_fun, args_maker, check_dtypes=True,
                           check_incomplete_shape=True,
@@ -1301,8 +1301,12 @@ def testCumSumProd(self, axis, shape, dtype, out_dtype, onp_op, lnp_op, rng_fact
                             tol=tol)
     # XLA lacks int64 Cumsum/Cumprod kernels (b/168841378).
     check_xla = out_dtype != onp.int64
+    rtol = None
+    if out_dtype == onp.float16:
+      rtol = 2e-3
     self._CompileAndCheck(
-        lnp_fun, args_maker, check_dtypes=True, check_incomplete_shape=True,
+        lnp_fun, args_maker, check_dtypes=True, rtol=rtol,
+        check_incomplete_shape=True,
         check_experimental_compile=check_xla,
         check_xla_forced_compile=check_xla)
 
diff --git a/trax/tf_numpy/jax_tests/test_util.py b/trax/tf_numpy/jax_tests/test_util.py
index fae593759..b12b04676 100644
--- a/trax/tf_numpy/jax_tests/test_util.py
+++ b/trax/tf_numpy/jax_tests/test_util.py
@@ -333,8 +333,10 @@ def format_test_name_suffix(opname, shapes, dtypes):
 
 # We use special symbols, represented as singleton objects, to distinguish
 # between NumPy scalars, Python scalars, and 0-D arrays.
-class ScalarShape(object):
+class ScalarShape:
   def __len__(self): return 0
+  def __getitem__(self, i):
+    raise IndexError(f'index {i} out of range.')
 class _NumpyScalar(ScalarShape): pass
 class _PythonScalar(ScalarShape): pass
 NUMPY_SCALAR_SHAPE = _NumpyScalar()