Assert correct class of arrays returned by ivy and frontend functions…

…/methods (ivy-llc#19183)

ivy_tests/test_ivy/helpers/function_testing.py

@@ -280,6 +280,10 @@ def test_function(
             **kwargs,
         )
 
+        assert ivy_backend.nested_map(
+            ret_from_target, lambda x: ivy_backend.is_ivy_array(x) if ivy_backend.is_array(x) else True
+        ), "Ivy function returned non-ivy arrays: {}".format(ret_from_target)
+
         # Assert indices of return if the indices of the out array provided
         if test_flags.with_out and not test_flags.test_compile:
             test_ret = (
@@ -382,6 +386,9 @@ def test_function(
             test_compile=test_flags.test_compile,
             **kwargs,
         )
+        assert gt_backend.nested_map(
+            ret_from_gt, lambda x: gt_backend.is_ivy_array(x) if gt_backend.is_array(x) else True
+        ), "Ground-truth function returned non-ivy arrays: {}".format(ret_from_gt)
         if test_flags.with_out and not test_flags.test_compile:
             test_ret_from_gt = (
                 ret_from_gt[getattr(gt_backend.__dict__[fn_name], "out_index")]
@@ -611,6 +618,10 @@ def test_frontend_function(
             **kwargs_for_test,
         )
 
+        assert ivy_backend.nested_map(
+            ret, lambda x: _is_frontend_array(x) if ivy_backend.is_array(x) else True
+        ), "Frontend function returned non-frontend arrays: {}".format(ret)
+
         if test_flags.with_out:
             if not inspect.isclass(ret):
                 is_ret_tuple = issubclass(ret.__class__, tuple)
@@ -1219,6 +1230,10 @@ def test_method(
         else:
             ret_device = None
 
+        assert ivy_backend.nested_map(
+            ret, lambda x: ivy_backend.is_ivy_array(x) if ivy_backend.is_array(x) else True
+        ), "Ivy method returned non-ivy arrays: {}".format(ret)
+
     # Compute the return with a Ground Truth backend
 
     with update_backend(ground_truth_backend) as gt_backend:
@@ -1262,7 +1277,10 @@ def test_method(
             test_compile=test_compile,
             **kwargs_gt_method,
         )
-
+        assert gt_backend.nested_map(
+            ret_from_gt, lambda x: gt_backend.is_ivy_array(x) if gt_backend.is_array(x) else True
+        ), "Ground-truth method returned non-ivy arrays: {}".format(ret_from_gt)
+
         # TODO optimize or cache
         # Exhuastive replication for all examples
         fw_list = gradient_unsupported_dtypes(fn=ins.__getattribute__(method_name))
@@ -1580,6 +1598,10 @@ def test_frontend_method(
             **kwargs_method,
         )
 
+        assert ivy_backend.nested_map(
+            ret, lambda x: _is_frontend_array(x) if ivy_backend.is_array(x) else True
+        ), "Frontend method returned non-frontend arrays: {}".format(ret)
+
     # Compute the return with the native frontend framework
     frontend_config = get_frontend_config(frontend)
     args_constructor_frontend = ivy.nested_map(