nkeywal created HBASE-6884:
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Summary: Update documentation on unit tests
Key: HBASE-6884
URL: https://issues.apache.org/jira/browse/HBASE-6884
Project: HBase
Issue Type: Improvement
Components: documentation
Affects Versions: 0.96.0
Reporter: nkeywal
Priority: Minor
Fix For: 0.96.0
Points to address:
- we don't have anymore JUnit rules in the tests
- we should document how to run the test faster.
- some stuff is not used (run only a category) and should be removed from the
doc imho.
Below the proposal:
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15.6.2. Unit Tests
HBase unit tests are subdivided into three categories: small, medium and large,
with corresponding JUnit categories: SmallTests, MediumTests, LargeTests. JUnit
categories are denoted using java annotations and look like this in your unit
test code.
...
@Category(SmallTests.class)
public class TestHRegionInfo {
@Test
public void testCreateHRegionInfoName() throws Exception {
// ...
}
}
The above example shows how to mark a test as belonging to the small category.
HBase uses a patched maven surefire plugin and maven profiles to implement its
unit test characterizations.
15.6.2.4. Running tests
Below we describe how to run the HBase junit categories.
15.6.2.4.1. Default: small and medium category tests
Running
mvn test
will execute all small tests in a single JVM (no fork) and then medium tests in
a separate JVM for each test instance. Medium tests are NOT executed if there
is an error in a small test. Large tests are NOT executed. There is one report
for small tests, and one report for medium tests if they are executed.
15.6.2.4.2. Running all tests
Running
mvn test -P runAllTests
will execute small tests in a single JVM then medium and large tests in a
separate JVM for each test. Medium and large tests are NOT executed if there is
an error in a small test. Large tests are NOT executed if there is an error in
a small or medium test. There is one report for small tests, and one report for
medium and large tests if they are executed
15.6.2.4.3. Running a single test or all tests in a package
To run an individual test, e.g. MyTest, do
mvn test -P localTests -Dtest=MyTest
You can also pass multiple, individual tests as a comma-delimited list:
mvn test -P localTests -Dtest=MyTest1,MyTest2,MyTest3
You can also pass a package, which will run all tests under the package:
mvn test -P localTests -Dtest=org.apache.hadoop.hbase.client.*
The -P localTests will remove the JUnit category effect (without this specific
profile, the categories are taken into account). Each junit tests is executed
in a separate JVM (A fork per test class). There is no parallelization when
localTests profile is set. You will see a new message at the end of the report:
"[INFO] Tests are skipped". It's harmless.
15.6.2.4.4. Running test faster
[replace previous chapter]
By default, mvn test -P runAllTests runs 5 tests in parallel. It can be
increased for many developper machine. Consider that you can have 2 tests in
parallel per core, and you need about 2Gb of memory per test. Hence, if you
have a 8 cores and 24Gb box, you can have 16 tests in parallel.
The setting is:
mvn test -P runAllTests -Dsurefire.secondPartThreadCount=12
To increase the speed, you can as well use a ramdisk. You will need 2Gb of
memory to run all the test. You will also need to delete the files between two
test run.
The typical way to configure a ramdisk on Linux is:
sudo mkdir /ram2G
sudo mount -t tmpfs -o size=2048M tmpfs /ram2G
You can then use it to run all HBase tests with the command:
mvn test -P runAllTests -Dsurefire.secondPartThreadCount=8
-Dtest.build.data.basedirectory=/ram2G
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