Glancing at TestNG and JUnit4, the grouping stuff looks nicer in TestNG.
But does grouping help except when changes are in high-level
components that little else depends on? For example, a change to HDFS
should run all the mapred tests that depend on it. So if groups are
tags (as I think they are in TestNG) then we could tag those mapred
tests that also use HDFS as belonging in the HDFS group too. But that
may not help overall execution time in many cases, e.g., a change to
HDFS would still require that all the slow tests be run. It might still
be worth trying groups...
Another approach to speeding tests might be to reuse static MiniDFS and
MiniMR daemons. We could have a static method like,
getMiniDFS(..params..). If one is already running with those params, it
can be reused, otherwise the running instance is shutdown and a new
instance started. Then. if we have control of the ordering of tests, we
can arrange for tests that use the same minimr and/or minidfs
configurations to run in sequence.
Doug
Nigel Daley wrote:
On Feb 22, 2007, at 10:55 AM, Doug Cutting (JIRA) wrote:
[snip]
Each 'ant clean test' run took 16.5 minutes. I wonder if we could
decrease that substantially by merging several tests that start dfs or
mapred daemons into a single test, so that daemons are started and
stopped fewer times? We could even run test jobs in separate threads,
so that, e.g., while one test's reduce tasks are running another tests
map tasks can run...
I think merging or overlapping tests complicates the analysis of tests
when they fail (which is already hard enough).
Perhaps another solution is to categorize our tests so that developers
can choose subsets of the tests to run. This could be achieved through
new ant targets (yuk!) or replacing JUnit with a test harness that
supports categorization. TestNG (http://testng.org/) is such a harness
-- and it runs all JUnit tests without modification. It's licensed
under Apache License 2.0. Another possibility is upgrade our JUnit to
version 4 (good walk through here:
http://today.java.net/pub/a/today/2006/12/07/junit-reloaded.html) which
seems to have a rudimentary categorization scheme using annotated test
suites.
Nige
