The page in the URL explains the old style of physical plan output.
The current style adds "*" as a prefix of each operation that the whole-stage codegen can be apply to.

So, in your test case, whole-stage codegen has been already enabled!!

FYI. I think that it is a good topic for dev@spark.apache.org.

Kazuaki Ishizaki

From:        Koert Kuipers <koert@tresata.com>
To:        "user@spark.apache.org" <user@spark.apache.org>
Date:        2017/04/05 05:12
Subject:        how do i force unit test to do whole stage codegen

i wrote my own expression with eval and doGenCode, but doGenCode never gets called in tests.

also as a test i ran this in a unit test:
spark.range(10).select('id as 'asId).where('id === 4).explain

according to
this is supposed to show:
== Physical Plan ==
:  +- Project [id#0L AS asId#3L]
:     +- Filter (id#0L = 4)
:        +- Range 0, 1, 8, 10, [id#0L]

but it doesn't. instead it shows:

== Physical Plan ==
*Project [id#12L AS asId#15L]
+- *Filter (id#12L = 4)
  +- *Range (0, 10, step=1, splits=Some(4))

so i am again missing the WholeStageCodegen. any idea why?

i create spark session for unit tests simply as:
val session = SparkSession.builder
 .config("spark.sql.shuffle.partitions", 4)