[SPARK-18338][SQL][test-maven] Fix test case initialization order under Maven builds

[liancheng]

What changes were proposed in this pull request?

Test case initialization order under Maven and SBT are different. Maven always creates instances of all test cases and then run them all together.

This fails ObjectHashAggregateSuite because the randomized test cases there register a temporary Hive function right before creating a test case, and can be cleared while initializing other successive test cases. In SBT, this is fine since the created test case is executed immediately after creating the temporary function.

To fix this issue, we should put initialization/destruction code into beforeAll() and afterAll().

How was this patch tested?

Existing tests.

[SparkQA]

Test build #68306 has finished for PR 15802 at commit 7b9a3cb.

• This patch fails Spark unit tests.
• This patch merges cleanly.
• This patch adds no public classes.

[yhuai]

Seems it does not work with sbt?

[zsxwing]

Could you add [test-maven] to the title to run the PR with maven build?

[zsxwing]

Seems it does not work with sbt?

I saw the same java.lang.OutOfMemoryError: Java heap space in my PR as well. I think it's just because these tests are flaky.

[liancheng]

@cloud-fan already reported the OOM issue. I'm trying to reproduce it locally.

Added the [test-maven] tag to trigger Maven tests.

[liancheng]

retest this please

[SparkQA]

Test build #68355 has finished for PR 15802 at commit 7b9a3cb.

• This patch fails Spark unit tests.
• This patch merges cleanly.
• This patch adds no public classes.

[liancheng]

retest this please.

[liancheng]

The last build failure was caused by an irrelevant flaky test.

BTW, I've reproduced the OOM issue locally by running ObjectHashAggregateSuite 200 times within a single SBT REPL session. Analyzing the heap dump.

[SparkQA]

Test build #68365 has finished for PR 15802 at commit 7b9a3cb.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[yhuai]

I am going to merge this to fix maven build.