diff --git a/test/test_onnx.py b/test/test_onnx.py
index cacc3265..87122819 100644
--- a/test/test_onnx.py
+++ b/test/test_onnx.py
@@ -2,25 +2,24 @@
 """
 Test for exporting model to ONNX and inference with ONNXRuntime
 """
-import io
-import unittest
+from typing import List, Tuple
 
-try:
-    # This import should be before that of torch if you are using PyTorch lower than 1.5.0
-    # see <https://github.com/onnx/onnx/issues/2394#issuecomment-581638840>
-    import onnxruntime
-except ImportError:
-    onnxruntime = None
+from pathlib import Path
+import io
+import pytest
 
 import torch
+from torch import Tensor
 from torchvision.ops._register_onnx_ops import _onnx_opset_version
 
 from yolort.models import yolov5s, yolov5m, yolotr
-from yolort.utils import get_image_from_url, read_image_to_tensor
 
+# In environments without onnxruntime we prefer to
+# invoke all tests in the repo and have this one skipped rather than fail.
+onnxruntime = pytest.importorskip("onnxruntime")
 
-@unittest.skipIf(onnxruntime is None, 'ONNX Runtime unavailable')
-class ONNXExporterTester(unittest.TestCase):
+
+class TestONNXExporter:
     @classmethod
     def setUpClass(cls):
         torch.manual_seed(123)
@@ -53,10 +52,10 @@ def run_model(self, model, inputs_list, tolerate_small_mismatch=False,
         # validate the exported model with onnx runtime
         for test_inputs in inputs_list:
             with torch.no_grad():
-                if isinstance(test_inputs, torch.Tensor) or isinstance(test_inputs, list):
+                if isinstance(test_inputs, Tensor) or isinstance(test_inputs, list):
                     test_inputs = (test_inputs,)
                 test_ouputs = model(*test_inputs)
-                if isinstance(test_ouputs, torch.Tensor):
+                if isinstance(test_ouputs, Tensor):
                     test_ouputs = (test_ouputs,)
             self.ort_validate(onnx_io, test_inputs, test_ouputs, tolerate_small_mismatch)
 
@@ -88,18 +87,19 @@ def to_numpy(tensor):
                 else:
                     raise
 
-    def get_test_images(self):
-        image_url = "https://github.com/ultralytics/yolov5/raw/master/data/images/bus.jpg"
-        image = get_image_from_url(image_url)
-        image = read_image_to_tensor(image, is_half=False)
+    def get_image(self, rel_path, size) -> Tensor:
+        from PIL import Image
+        from torchvision import transforms
+        data_path = Path(__file__).parent.resolve() / "assets"
+
+        img_path = data_path / rel_path
+        image = Image.open(img_path).convert("RGB").resize(size, Image.BILINEAR)
 
-        image_url2 = "https://github.com/ultralytics/yolov5/raw/master/data/images/zidane.jpg"
-        image2 = get_image_from_url(image_url2)
-        image2 = read_image_to_tensor(image2, is_half=False)
+        return transforms.ToTensor()(image)
 
-        images_one = [image]
-        images_two = [image2]
-        return images_one, images_two
+    def get_test_images(self) -> Tuple[List[Tensor], List[Tensor]]:
+        return ([self.get_image("bus.jpg", (416, 320))],
+                [self.get_image("zidane.png", (352, 480))])
 
     def test_yolov5s_r31(self):
         images_one, images_two = self.get_test_images()