Test for lfilter

Author: Sam Anklesaria

test/torchaudio_unittest/test_me.py

@@ -1,4 +1,4 @@
-from torchaudio.functional.filtering import iir, sams_matmul
+from torchaudio.functional.filtering import iir, lfilter
 import torch
 from torch.autograd import gradcheck
 
@@ -11,3 +11,9 @@ def test_iir():
     w = torch.rand((1, 1, 10), requires_grad=True, dtype=torch.float64)
     a = torch.rand((1, 4), requires_grad=True, dtype=torch.float64)
     gradcheck(iir, (w, a))
+
+def test_lfilter():
+    w = torch.rand(10, requires_grad=True, dtype=torch.float64)
+    a = torch.rand(4, requires_grad=True, dtype=torch.float64)
+    b = torch.rand(4, requires_grad=True, dtype=torch.float64)
+    gradcheck(lfilter, (w, a, b))