[Test][Relay][Pass] Add test case for lambda lift (#4317)

tests/python/relay/test_pass_lambda_lift.py

+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+import numpy as np
+import pytest
+
+import tvm
+from tvm import relay
+from tvm.relay import transform
+
+def test_basic():
+    mod = relay.Module()
+    x2 = relay.var('x2', shape=(10, 5))
+    y2 = relay.var('y2', shape=(1, 5))
+    level2_func = relay.Function([x2, y2], relay.op.add(x2, y2))
+
+    x1 = relay.var('x1', shape=(10, 5))
+    y1 = relay.var('y1', shape=(1, 5))
+    level1_func = relay.Function([x1, y1], level2_func(x1, y1))
+
+    mod["main"] = level1_func
+    new_mod = transform.LambdaLift()(mod)
+    assert len(new_mod.functions) == 2
+
+if __name__ == "__main__":
+    pytest.main()
+