Added tests for gain

Author: CamiWilliams

test/assets/sinewave_soxgain5.wav

@@ -7,6 +7,7 @@
 import pytest
 import unittest
 import common_utils
+import os
 
 from torchaudio.common_utils import IMPORT_LIBROSA
 
@@ -247,6 +248,19 @@ def test_create_fb(self):
         self._test_create_fb(n_mels=56, fmin=1900.0, fmax=900.0)
         self._test_create_fb(n_mels=10, fmin=1900.0, fmax=900.0)
 
+    def test_gain(self):
+        test_dirpath, test_dir = common_utils.create_temp_assets_dir()
+        test_filepath = os.path.join(test_dirpath, "assets", "sinewave.wav")
+
+        waveform, sample_rate = torchaudio.load(test_filepath)
+        waveform_gain = F.gain(waveform, 5)
+        self.assertTrue(waveform_gain.abs().max().item(), 1.)
+
+        test_filepath_sox_gain = os.path.join(test_dirpath, "assets", "sinewave_soxgain5.wav")
+        sox_gain_waveform, sox_sr = torchaudio.load(test_filepath_sox_gain)
+
+        self.assertTrue(torch.allclose(waveform_gain, sox_gain_waveform))
+
 
 def _num_stft_bins(signal_len, fft_len, hop_length, pad):
     return (signal_len + 2 * pad - fft_len + hop_length) // hop_length
@@ -346,5 +360,6 @@ def test_mask_along_axis_iid(specgrams, mask_param, mask_value, axis):
     assert (num_masked_columns < mask_param).sum() == num_masked_columns.numel()
 
 
+
 if __name__ == '__main__':
     unittest.main()