test scriptify MultiheadAttention (#670)

Summary:
Pull Request resolved: #670

We introduce a new test suite where we will iteratively ensure that various model components are TorchScript compliant (JIT-able).

Differential Revision: D18799715

fbshipit-source-id: b4a1486080f6791d1fcfeaa51edc4a38c4fadc20

Author: jhcross

pytorch_translate/test/test_export_models.py

@@ -0,0 +1,13 @@
+#!/usr/bin/env python3
+
+import unittest
+
+import torch
+from fairseq.modules import multihead_attention
+
+
+class TestExportModels(unittest.TestCase):
+    @unittest.skip("TDD: placeholder for development")
+    def test_export_multihead_attention(self):
+        module = multihead_attention.MultiheadAttention(embed_dim=8, num_heads=2)
+        torch.jit.script(module)