Add test case for expr_functor.py (#2632)

python/tvm/relay/expr_functor.py

 # pylint: disable=no-else-return, unidiomatic-typecheck, invalid-name
 """The expression functor of Relay."""
 
-from .expr import Function, Call, Let, Var, GlobalVar, If, Tuple, TupleGetItem, Constant
+from .expr import Function, Call, Let, Var, GlobalVar
+from .expr import If, Tuple, TupleGetItem, Constant
+from .expr import RefCreate, RefRead, RefWrite
 from .adt import Constructor, Match, Clause
 from .op import Op
 

tests/python/relay/test_expr_functor.py

+import tvm
+from tvm import relay
+from tvm.relay import ExprFunctor, ExprMutator
+
+def check_visit(expr):
+    ef = ExprFunctor()
+    try:
+        ef.visit(expr)
+        assert False
+    except NotImplementedError:
+        pass
+
+    em = ExprMutator()
+    assert em.visit(expr)
+
+def test_constant():
+    check_visit(relay.const(1.0))
+
+def test_tuple():
+    t = relay.Tuple([relay.var('x', shape=())])
+    check_visit(t)
+
+def test_var():
+    v = relay.var('x', shape=())
+    check_visit(v)
+
+def test_global():
+    v = relay.GlobalVar('f')
+    check_visit(v)
+
+def test_function():
+    x = relay.var('x', shape=())
+    y = relay.var('y', shape=())
+    params = [x, y]
+    body = x + y
+    ret_type = relay.TensorType(())
+    type_params = []
+    attrs = None # How to build?
+    f = relay.Function(
+        params,
+        body,
+        ret_type,
+        type_params,
+        attrs
+    )
+    check_visit(f)
+
+def test_call():
+    x = relay.var('x', shape=())
+    y = relay.var('y', shape=())
+    call = relay.op.add(x, y)
+    check_visit(call)
+
+def test_let():
+    x = relay.var('x', shape=())
+    value = relay.const(2.0)
+    body = x + x
+    l = relay.Let(x, value, body)
+    check_visit(l)
+
+def test_ite():
+    cond = relay.var('x', shape=(), dtype='bool')
+    ite = relay.If(cond, cond, cond)
+    check_visit(ite)
+
+def test_get_item():
+    t = relay.Tuple([relay.var('x', shape=())])
+    t = relay.TupleGetItem(t, 0)
+    check_visit(t)
+
+def test_ref_create():
+    r = relay.expr.RefCreate(relay.const(1.0))
+    check_visit(r)
+
+def test_ref_read():
+    ref = relay.expr.RefCreate(relay.const(1.0))
+    r = relay.expr.RefRead(ref)
+    check_visit(r)
+
+def test_ref_write():
+    ref = relay.expr.RefCreate(relay.const(1.0))
+    r = relay.expr.RefWrite(ref, relay.const(2.0))
+    check_visit(r)
+
+if __name__ == "__main__":
+    test_constant()
+    test_tuple()
+    test_var()
+    test_global()
+    test_function()
+    test_call()
+    test_let()
+    test_ite()
+    test_ref_create()
+    test_ref_read()
+    test_ref_write()