The most widely used Mandarin proficiency test is
the 汉语水平考试 or HSK (Hanyu Shuiping Kaoshi).
The test is used for proficiency certification that
may be required by Chinese universities and
professional organizations.
version of the HSK, although I have heard that the
"new HSK" has been in use for at least a year now.
Nonetheless, the Examiner article contains some
interesting comments about the nature of the
exam and its application in daily life:
"If you pass Level 3 and immerse yourself
in Beijing for months, you will have no problem
interacting with the locals," said Mr Zhou. "
But even if you obtain Level 6, if you are not
soaked in a conducive language environment,
you most probably will still struggle to converse
or read Chinese newspapers."
There are six levels to the HSK, and each level consists
of a writing test and a speaking test. Level One candidates
must know 150 words, while the Level Six tests expects a
knowledge of more than 5,000 words. You can read more
about the HSK requirements at this link