Improve local mode transformer test (aws#430)

Add a lock for the transformer test, similar to the serving tests
as the serving container will still run on the same port. Also remove
this test from the continuous testing suite.

Author: iquintero

tests/integ/test_local_mode.py

@@ -368,8 +368,9 @@ def test_mxnet_local_data_local_script():
         fcntl.lockf(local_mode_lock, fcntl.LOCK_UN)
 
 
-@pytest.mark.continuous_testing
 def test_local_transform_mxnet(sagemaker_local_session, tmpdir):
+    local_mode_lock_fd = open(LOCK_PATH, 'w')
+    local_mode_lock = local_mode_lock_fd.fileno()
     data_path = os.path.join(DATA_DIR, 'mxnet_mnist')
     script_path = os.path.join(data_path, 'mnist.py')
 
@@ -392,7 +393,13 @@ def test_local_transform_mxnet(sagemaker_local_session, tmpdir):
     output_path = 'file://%s' % (str(tmpdir))
     transformer = mx.transformer(1, 'local', assemble_with='Line', max_payload=1,
                                  strategy='SingleRecord', output_path=output_path)
+
+    # Since Local Mode uses the same port for serving, we need a lock in order
+    # to allow concurrent test execution.
+    fcntl.lockf(local_mode_lock, fcntl.LOCK_EX)
     transformer.transform(transform_input, content_type='text/csv', split_type='Line')
     transformer.wait()
+    time.sleep(5)
+    fcntl.lockf(local_mode_lock, fcntl.LOCK_UN)
 
     assert os.path.exists(os.path.join(str(tmpdir), 'data.csv.out'))