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All public classes and methods should have informative Javadoc comments.
- Do not use @author tags.
Code must be formatted according to Sun's conventions, with one exception:
- Indent two spaces per level, not four.
- Code formatter xml is present here: https://github.com/apache/hadoop/tree/trunk/dev-support/code-formatter . IntelliJ users can directly import
hadoop_idea_formatter.xml - Contributions must pass existing unit tests.
New unit tests should be provided to demonstrate bugs and fixes. JUnit is our test framework:
You must implement a class that uses @Test annotations for all test methods. Please note, Hadoop uses JUnit v4.
Define methods within your class whose names begin with test, and call JUnit's many assert methods to verify conditions; these methods will be executed when you run mvn test. Please add meaningful messages to the assert statement to facilitate diagnostics.
By default, do not let tests write any temporary files to /tmp. Instead, the tests should write to the location specified by the test.build.data system property.
If a HDFS cluster or a MapReduce/YARN cluster is needed by your test, please use org.apache.hadoop.dfs.MiniDFSCluster and org.apache.hadoop.mapred.MiniMRCluster (or org.apache.hadoop.yarn.server.MiniYARNCluster), respectively. TestMiniMRLocalFS is an example of a test that uses MiniMRCluster.
Place your class in the src/test tree.
TestFileSystem.java and TestMapRed.java are examples of standalone MapReduce-based tests.
TestPath.java is an example of a non MapReduce-based test.
You can run all the project unit tests with mvn test, or a specific unit test with mvn -Dtest=<class name without package prefix> test. Run these commands from the hadoop-trunk directory.
If you modify the Unix shell scripts, see the UnixShellScriptProgrammingGuide.
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