Add test for frames

test/torchaudio_unittest/sox_io_backend/load_test.py

@@ -509,3 +509,25 @@ def test_requests(self, ext, compression):
 
         assert sr == sample_rate
         self.assertEqual(expected, found)
+
+    @parameterized.expand(list(itertools.product(
+        [0, 1, 10, 100, 1000],
+        [-1, 1, 10, 100, 1000],
+    )), name_func=name_func)
+    def test_frame(self, frame_offset, num_frames):
+        """num_frames and frame_offset correctly specify the region of data"""
+        sample_rate = 8000
+        audio_file = f'test.wav'
+        audio_path = self.get_temp_path(audio_file)
+
+        original = get_wav_data('float32', num_channels=2)
+        save_wav(audio_path, original, sample_rate)
+        frame_end = None if num_frames == -1 else frame_offset + num_frames
+        expected = original[:, frame_offset:frame_end]
+
+        url = self.get_url(audio_file)
+        with requests.get(url, stream=True) as resp:
+            found, sr = sox_io_backend.load(resp.raw, frame_offset, num_frames)
+
+        assert sr == sample_rate
+        self.assertEqual(expected, found)