Oracle quirks: Comparing NULL

Our Oracle database just keeps amazing me. Given the following testcase:

SELECT
  CASE WHEN NULL = '' THEN 1 ELSE 0 END as nullvsemptystring,
  CASE WHEN NULL = NULL THEN 1 ELSE 0 END as nullvsnull,
  CASE WHEN NULL = 'asdf' THEN 1 ELSE 0 END as nullvsstring
FROM DUAL

Expected:

nullvsemptystring - 0
nullvsnull - 1
nullvsstring - 0

But we got nullvsnull - 0?

After a bit of digging on the internet i found this article by Robbert Vollman: Nulls in Oracle. Seems Oracle got me again.

To compare against NULL you need to use IS NULL (explicitly saying it should be null)

SELECT
  CASE WHEN NULL IS NULL THEN 1 ELSE 0 END as nullvsnull
FROM DUAL