Add test code

torch_integrated_conv/integrated_conv_test.py

+import torch
+from torch_integrated_conv import integrated_conv
+
+
+def test_integrated_conv_zeros():
+    N = 1
+    C = 2
+    H = 3
+    W = 4
+    for device in [ torch.device('cpu'), torch.device('cuda:0') ]:
+        for dtype in [torch.float32, torch.float64]:
+            print("device=", device, ", dtype=", dtype)
+            input = torch.zeros(N, 2 * C, H, W, device=device, dtype=dtype)
+            kH = 5
+            kW = 5
+            pos_add = torch.zeros(C, kH, kW, device=device, dtype=dtype)
+            pos_mul = torch.zeros(C, kH, kW, device=device, dtype=dtype)
+
+            output = integrated_conv(input, pos_add, pos_mul)
+            assert torch.allclose(input, output)