Add autograd test

Author: mthrok

test/torchaudio_unittest/transforms/autograd_test_impl.py

@@ -8,6 +8,7 @@
 from torchaudio_unittest.common_utils import (
     TestBaseMixin,
     get_whitenoise,
+    nested_params,
 )
 
 
@@ -94,3 +95,12 @@ def test_spectral_centroid(self):
         transform = T.SpectralCentroid(sample_rate=sample_rate)
         waveform = get_whitenoise(sample_rate=sample_rate, duration=0.05, n_channels=2)
         self.assert_grad(transform, [waveform], nondet_tol=1e-10)
+
+    @nested_params(
+        [0, 0.99],
+        [False, True],
+    )
+    def test_griffinlim(self, momentum, rand_init):
+        transform = T.GriffinLim(n_fft=400, momentum=momentum, rand_init=rand_init)
+        spec = torch.randn(2, 1, 201, 15)
+        self.assert_grad(transform, [spec])