Port test_models_detection_anchor_utils.py to pytest (#4046)

test/test_models_detection_anchor_utils.py

@@ -3,6 +3,7 @@ from common_utils import TestCase
 from _assert_utils import assert_equal
 from torchvision.models.detection.anchor_utils import AnchorGenerator, DefaultBoxGenerator
 from torchvision.models.detection.image_list import ImageList
+import pytest
 
 
 class Tester(TestCase):
@@ -13,7 +14,7 @@ class Tester(TestCase):
         image1 = torch.randn(3, 800, 800)
         image_list = ImageList(image1, [(800, 800)])
         feature_maps = [torch.randn(1, 50)]
-        self.assertRaises(ValueError, anc, image_list, feature_maps)
+        pytest.raises(ValueError, anc, image_list, feature_maps)
 
     def _init_test_anchor_generator(self):
         anchor_sizes = ((10,),)
@@ -59,10 +60,10 @@ class Tester(TestCase):
                                        [0., 5., 10., 15.],
                                        [5., 5., 15., 15.]])
 
-        self.assertEqual(num_anchors_estimated, 9)
-        self.assertEqual(len(anchors), 2)
-        self.assertEqual(tuple(anchors[0].shape), (9, 4))
-        self.assertEqual(tuple(anchors[1].shape), (9, 4))
+        assert num_anchors_estimated == 9
+        assert len(anchors) == 2
+        assert tuple(anchors[0].shape) == (9, 4)
+        assert tuple(anchors[1].shape) == (9, 4)
         assert_equal(anchors[0], anchors_output)
         assert_equal(anchors[1], anchors_output)
 
@@ -83,8 +84,8 @@ class Tester(TestCase):
             [6.7045, 5.9090, 8.2955, 9.0910]
         ])
 
-        self.assertEqual(len(dboxes), 2)
-        self.assertEqual(tuple(dboxes[0].shape), (4, 4))
-        self.assertEqual(tuple(dboxes[1].shape), (4, 4))
+        assert len(dboxes) == 2
+        assert tuple(dboxes[0].shape) == (4, 4)
+        assert tuple(dboxes[1].shape) == (4, 4)
         torch.testing.assert_close(dboxes[0], dboxes_output, rtol=1e-5, atol=1e-8)
         torch.testing.assert_close(dboxes[1], dboxes_output, rtol=1e-5, atol=1e-8)